Complete Curtain & Window Treatment Glossary: 60 Terms Decoded

A curtain glossary is a plain-English reference of every term used when buying, measuring, hanging, and living with window treatments. This one covers 60 terms across 7 clusters: fabric, header, lining, measurement, style, hardware, and service.

The 7 clusters match the order a real buyer meets the vocabulary. Fabric decides feel and cost. Header decides drape shape. Lining decides light. Measurement decides fit. Style decides how it reads in the room. Hardware decides what holds it up. Service decides how long you wait and what happens if a dye lot is off.

Use the reference matrix below for a 30-second scan, the decision flowchart when you know your intent but not the vocabulary, and the cluster sections for the full definition. For the deeper picture on how these terms play out across a real collection, jump to the complete linen curtains guide.

Glossary Reference Matrix (Scan Before You Scroll)

Twenty-four high-frequency terms surface here for anyone who lands on the page for a single answer. Every entry drops back into its cluster below with the full definition and Two Pages equivalent. If you need alphabetical navigation instead of cluster-by-cluster reading, the window treatment terminology matrix handles that.

Term	Cluster	One-line definition	Two Pages equivalent
GSM	Fabric	Grams per square meter, fabric weight standard.	Liz Linen 350 gsm heavyweight.
Slub texture	Fabric	Uneven yarn thickness typical of linen weaves.	Standard Liz Linen surface.
Blackout composite	Fabric	Multi-layer coated fabric rated 100% light block.	Lila Coated Blackout.
Pinch pleat	Header	2 to 4 finger pleats stitched every 4 to 6 inches.	Liz Linen default header.
Rod pocket	Header	Sewn channel that slides onto the rod.	Flat rod pocket, 1.5x fullness.
Grommet	Header	Metal-rimmed hole at panel top, rod slips through.	Liz Linen grommet variant.
Ripple fold	Header	Track carriers producing continuous S-wave drape.	Liz Linen ripple fold variant.
Fullness ratio	Header	Multiplier of rod width to flat panel width.	2x default, 2.5x sheer, 3x luxury.
Unlined	Lining	Single layer, no backing, translucent behavior.	Available across most collections.
Room-darkening lining	Lining	Multi-layer, blocks 85 to 95 percent of light.	Room-darkening upgrade option.
Blackout lining	Lining	Coated multi-layer, 100 percent light block.	Blackout lining upgrade option.
Rod width	Measurement	Distance between the two rod brackets or track ends.	Input 1 of the configurator.
Finished drop	Measurement	Vertical panel length from header top to hem.	Input 2 of the configurator.
Floor kiss	Measurement	Drop that stops 1/2 inch above the floor.	Standard tailored drop.
Puddle	Measurement	Drop 2 to 6 inches longer than floor, pools on floor.	Add 2 to 6 inches at configurator.
Return	Measurement	Distance from rod end back to wall, wraparound.	Standard 3 to 4 inches.
Stack back	Measurement	Horizontal space open panels occupy at rod ends.	15 to 20 percent of rod width per side.
Colorway	Style	Named color variant within a collection.	Liz Linen ships 38 colorways.
Dye lot	Style	Batch identifier for a single dye run.	Industry variance 2 to 3 percent.
Curtain rod	Hardware	Horizontal bar carrying panels above the window.	Sold by third parties, not Two Pages.
Bracket	Hardware	Wall or ceiling piece holding the rod.	Wall, ceiling, or extension type.
Made-to-order	Service	Panels sewn to your width and drop after order.	Every Two Pages custom SKU.
Memory training	Service	Post-production folding and steaming that sets pleats.	Add-on, 5 to 7 extra days.
Configurator	Service	Online form mapping vocabulary to product fields.	Standard on every Two Pages SKU.

Decision Flowchart: Which Term Do I Need?

Most buyers arrive with an intent, not a term. This flowchart maps 4 buyer contexts to the cluster that answers the question fastest.

Cluster 1: Fabric & Material Terms

Fabric decides how the drape feels, how it hangs, how it ages, and what it costs to ship. Nine terms cover the range from sheer voile to blackout composite.

GSM

Grams per square meter, the standard curtain fabric weight measurement. Under 100 reads as sheer, 100 to 160 as light drapery, 160 to 250 as mid-weight, 250 to 400 as heavyweight, and 400+ as blackout composite. Liz Linen ships at 350 gsm, which lands in the heavyweight tier for body and thermal behavior.

Fiber composition

The percentage split of every fiber in the fabric, printed on the spec sheet as `10% linen / 90% polyester` or similar. Composition decides drape softness, wrinkle behavior, cost, and how the fabric responds to steam and wash. Two Pages lists composition on every product page.

Linen (blend vs pure)

Linen is a flax-derived natural fiber prized for its slub texture and organic drape. A `pure linen` label means 100 percent linen fiber, more expensive and more prone to wrinkling. A `linen blend` mixes linen with polyester or cotton for stability. Liz Linen is a 10 percent linen / 90 percent polyester blend that reads linen in look and hand without the pure-linen wrinkle penalty.

Cotton

A natural fiber with a softer, matte drape than linen. Cotton curtains breathe well and take dye deeply, giving richer colorways than most synthetics. They wrinkle more than blends and shrink 3 to 8 percent on first wash if not pre-shrunk. Two Pages Isabella is the flagship cotton drapery collection.

Polyester blend

Polyester is a synthetic fiber that stabilizes drape, resists wrinkles, holds color under UV, and lowers the cost per panel. Blended at 70 to 90 percent with linen or cotton, it delivers a fabric that looks natural and behaves predictably. Most modern custom drapery collections use blends, not pure natural fiber.

Velvet

A pile fabric with a short, dense surface that catches and diffuses light. Velvet is the heaviest of the drapery fabrics, typically 400+ gsm, and reads formal and warm. It requires a sturdy rod and stronger brackets than linen or cotton. Two Pages Birkin and Veda Velour cover the velvet range.

Sheer fabric

An open-weave, translucent fabric under 100 gsm. Sheers filter light, blur the view without hiding it, and are paired with a second layer of drapery for real privacy. They ship at higher fullness (2.5x standard) to read fully gathered rather than stretched flat.

Blackout composite fabric

A single fabric rated for 100 percent light block without needing a separate lining. Blackout composites use 3 to 5 bonded layers with a coated core. They read heavier than standard blackout curtains with an added lining, and drop the install to a single panel per window. Atlanta Room Divider is the Two Pages example.

Colorfastness

A fabric’s resistance to color loss from light, washing, and rubbing. Rated on a scale of 1 to 5 under AATCC textile testing standards. Curtains take direct UV daily, so any rating below 4 fades visibly within 2 to 3 years. OEKO-TEX certified collections pair with high colorfastness in most catalogs.

Cluster 2: Header & Construction Terms

The header is the top edge of the panel, the part that meets the rod or track. It decides drape shape, fullness ratio, hardware fit, and how the drape reads across the wall. Nine header terms cover every mainstream option.

Pinch pleat

A header style where the top of the panel is folded and stitched into 2, 3, or 4 finger pleats spaced every 4 to 6 inches. It carries built-in 2x fullness, hangs on drapery hooks and rings, and produces the classic tailored drapery look. Liz Linen ships with a triple pinch pleat header as its default configuration.

Rod pocket

A sewn channel across the top of the panel that slides directly onto the rod. It reads casual, has no rings, and moves harder than a pleated panel because the fabric drags on the rod. Rod pocket ships at 1.5x fullness flat and is the cheapest header to produce.

Grommet

A metal-rimmed hole punched at regular intervals across the panel top, letting the rod pass through directly. Grommet reads modern, glides smoothly, and holds a soft S-wave between the openings. Standard fullness is 2x. The grommet diameter has to match the rod diameter within 1/4 inch.

Tab top and back tab

Tab top uses fabric loops sewn across the front of the panel that pass over the rod, reading casual and cottage. Back tab hides the loops behind the panel for a cleaner front face. Both ship at 1.8x to 2x fullness and cost less than pinch pleat.

Ripple fold

A track-based header where snap tape and carriers on a ceiling or wall track produce a continuous S-wave drape at 2.2x fullness. Ripple fold reads architectural and clean, is common in hotels, offices, and modern residential, and requires a track system rather than a standard rod.

Hidden tab

A back tab variant where the loops are stitched shorter and hidden behind the header band, giving a flat, tailored top edge with no rings or grommets visible. Fullness sits at 1.8x. It reads Scandinavian and pairs well with steel curtain rods and minimalist rooms.

Soft top and hook on

Soft top leaves the panel top unstitched, producing a drapey and slightly informal top edge on drapery hooks. Hook on uses a stiffened tape header stitched at the back, letting the buyer place removable hooks to set custom pinch pleat spacing. Both ship at 2x fullness.

Fullness ratio

The multiplier between rod width and total flat panel width across all panels. 2x fullness means a 60 inch rod carries 120 inches of flat panel combined, so the drape reads full rather than stretched. Sheers push to 2.5x, luxury drape reaches 3x, flat rod pocket stays at 1.5x.

Cluster 3: Lining & Light Control Terms

Lining is the second layer stitched behind the face fabric. It decides how much light passes through, how much heat the panel holds back, and how the drape hangs against a window. Seven lining terms cover the range from unlined to blackout composite.

Unlined

A single-layer panel with no backing fabric. Unlined curtains hang softer and drapier than lined ones, transmit 30 to 50 percent of light, and cost the least. They read casual and airy. Not a fit for bedrooms, home theaters, or south-facing rooms with strong afternoon sun.

Cotton lining

A neutral cotton fabric stitched behind the face panel to add body, protect the face fabric from UV fade, and lift shading to 55 to 65 percent. Cotton lining reads matte from the back, breathes well, and is the entry-level upgrade over unlined at Two Pages.

Sateen lining

A cotton or blend lining with a satin weave that gives a smoother back face and a slightly richer drape than plain cotton. Shading sits at 65 to 75 percent. Sateen also lets the front face fabric read more evenly across the panel, since the smoother back absorbs light more uniformly.

Thermal lining

A multi-layer lining engineered to slow heat transfer. Thermal lining lifts shading to 75 to 85 percent, cuts winter heat loss through the window, and reduces summer solar gain. It reads heavier than sateen and pairs best with heavier face fabrics like Liz Linen or Isabella.

Room-darkening lining

A denser multi-layer lining that blocks 85 to 95 percent of incoming light. It reads dark enough for living rooms, dining, offices, and most bedrooms, but a faint outline of light stays visible around the panel edges. Cheaper than full blackout and lighter to hang.

Blackout lining

A coated multi-layer lining rated for 100 percent light block. It is the only spec that reads truly dark at 7am in a south-facing bedroom. Blackout lining adds real weight to the panel and shifts hardware toward stronger brackets. Pair with a wide rod overhang to close the edge gap.

Interlining

A third fabric layer sewn between the face and the lining, used for luxury drape body and top-tier thermal performance. Interlining is common in high-end residential and hospitality installs. It reads noticeably heavier, hangs with more visible weight per pleat, and lifts price 25 to 40 percent over standard lining.

Cluster 4: Measurement Terms

Measurement is the cluster where most owners lose time and money. Nine terms cover every value the configurator asks for, plus the ones the install manual assumes you already know. When in doubt, cross-reference the Two Pages measurement guide before submitting the order.

Rod width

The horizontal distance between the two rod brackets or the two ends of a track. It is the first input on every configurator. The rod itself typically extends 6 to 12 inches beyond each side of the window frame to let panels stack off the glass when open.

Finished drop

The vertical length of the panel from the top of the header ring, grommet, or hook down to the bottom hem. It is the second configurator input. Standard drops follow the 4 conventions: sill, apron, floor kiss, puddle. Two Pages accepts custom drops to the 1/2 inch.

Sill / apron / floor kiss / puddle

The four drop conventions. Sill stops at the windowsill for a casual look. Apron ends below the sill trim. Floor kiss stops 1/2 inch above the finished floor for a tailored line. Puddle extends 2 to 6 inches onto the floor for a luxury pool of fabric.

Overhang

The distance the rod extends beyond each side of the window frame. Standard overhang is 6 to 12 inches per side. Wider overhang lets open panels clear the glass entirely, brightens the room, and makes the window read larger.

Return

The distance from the end of the rod back to the wall, covered by a wraparound end of the panel. Standard return is 3 to 4 inches. Return matters for blackout installs because the wrap closes the side gap where daylight sneaks past the panel edge.

Stack back

The horizontal space open panels occupy at each end of the rod when fully drawn. Typical stack back is 15 to 20 percent of the rod width per side at 2x fullness. Overhang has to be wide enough to absorb the stack back or the open panels will still cover part of the glass.

Center gap

The vertical seam where two panels meet in the middle. Center gap is unavoidable on 2-panel installs. A slight overlap of 2 to 3 inches at the center hides the seam, and adding a magnetic clip or hidden hook keeps the overlap closed when the drape is drawn.

Break

A soft fold at the base of the panel where the hem meets the floor at floor-kiss drop. A clean break reads tailored. Too little drop shows the floor gap. Too much drop compresses the hem into an unintended puddle. Two Pages recommends 0 to 1/2 inch break for floor kiss.

Panel count

The number of panels ordered per window. Two panels split at center is the residential default. Wide windows over 96 inches often use 3 or 4 panels to keep individual panel width workable during handling and cleaning. The Two Pages configurator suggests panel count based on rod width and header type.

Cluster 5: Style & Design Terms

Style vocabulary is the softer half of the glossary. It covers colorways, weaves, drape shapes, and the ways designers describe how a panel reads in a room. Eight terms.

Colorway

A named color variant within a collection, printed on the spec sheet as `Sand Beige 1908-3`, `Snow White 1908-0`, or similar. The number is the SKU variant. Liz Linen ships 38 colorways, which is the widest range Two Pages offers in a single collection.

Dye lot

The batch identifier for a single run of fabric dyed together. Two panels from different dye lots can vary 2 to 3 percent in exact hue. Two Pages cuts full orders from the same dye lot when possible. Reorders months later may pull from a different lot with visible variance under strong daylight.

Weave

The pattern in which warp and weft yarns cross. Plain weave reads flat and matte, sateen weave reads smooth and slightly glossy, twill weave reads diagonal, jacquard weave carries a pattern. Weave decides drape stiffness before fiber content does.

Slub texture

The uneven yarn thickness typical of linen and linen-blend weaves. Slub reads organic and hand-loomed. It is a feature of the fabric, not a defect. Liz Linen shows a moderate slub across the whole 350 gsm range and reads visibly linen-like under any light.

Drape shape

The way a panel falls between the header and the hem. Formal drape reads tailored and pleated, casual drape reads soft and gathered, architectural drape reads structured and precise (ripple fold). Header style and fullness ratio decide drape shape more than fabric does.

Pattern repeat

The vertical or horizontal distance between two identical points on a printed or woven pattern. Larger repeats need more fabric because pattern matching between panels wastes cut length. Solid Liz Linen has no repeat. Amy Switzer printed velvet carries a 24 to 36 inch repeat.

Layer system

A drapery install that stacks two or more panels on separate rods or a double rod. Sheer inner layer + drapery outer layer is the classic layer system for combined privacy and light control. Layer systems double the hardware count and roughly double the labor per window.

Motorization ready

A track or rod system pre-wired or pre-prepped for motorized carriers, letting the drape open and close from a remote or smart-home hub. Two Pages offers motorization on select collections, and most ripple fold tracks are motorization compatible out of the box.

Cluster 6: Hardware & Install Terms

Hardware is what holds the drape up. Two Pages ships panels, not rods, so this vocabulary is what you meet at the hardware store or the third-party rod vendor. Eight terms.

Curtain rod

The horizontal bar that carries the panels above the window. Standard rod diameters are 1 inch and 1.25 inch for residential, 1.5 to 2 inch for grommet and heavy drapery. Grommet diameter has to exceed rod diameter by 1/4 to 3/8 inch for smooth glide. Two Pages does not sell rods.

Finial

The decorative end cap screwed onto each end of the rod. Finials read as design detail. Common shapes are ball, cage, cylinder, spear, and disc. Rod width measured bracket-to-bracket excludes finials, but full rod length including finials adds 3 to 6 inches.

Bracket

The wall-mount or ceiling-mount piece that holds the rod. Wall brackets carry standard installs. Ceiling brackets drop the rod down from the ceiling, letting the drape read floor-to-ceiling. Extension brackets push the rod out from the wall by 4 to 8 inches to clear window trim.

Ring

A circular loop that slides on the rod, carrying a drapery hook that clips into the pinch pleat header at the back. Ring diameter has to exceed rod diameter by 1/2 to 3/4 inch for smooth movement. Standard drapery rings are metal, 1.5 to 2 inch inner diameter for a 1 inch rod.

Drapery hook

The metal hook that connects the pleated panel to a ring or track carrier. Standard drapery hooks are pin-on (pushed into the header from the back) or clip-on (clipped over the top edge). Two Pages ships pin-on hooks included with every pinch pleat order.

Track system

A ceiling-mount or wall-mount channel with rolling carriers, used for ripple fold and long-run drapery. Tracks glide smoother than rings on a rod and support motorization. Aluminum track is standard for residential. Two Pages supplies track systems for ripple fold installs.

Wall mount vs ceiling mount

The two rod-placement conventions. Wall mount places the rod on the wall above the window, standard 4 to 6 inches above the trim. Ceiling mount places the rod at the ceiling, making the drape read floor-to-ceiling and the window read taller. Ceiling mount adds 4 to 12 inches to finished drop.

Rod extension

The horizontal distance the rod extends past each side of the window frame, letting open panels stack off the glass. Standard rod extension is 6 to 12 inches per side. Wider extension brightens the room but requires more panel width to keep the closed drape covering the glass edge to edge.

Cluster 7: Service & Custom Order Terms

The service vocabulary is what happens between order submission and package arrival. Seven terms cover made-to-order, lead time, certifications, and the swatch process.

Made-to-order

Panels are sewn to the buyer’s exact width and drop after the order is placed. Every custom Two Pages SKU is made-to-order, which is why lead time is 10 to 12 days rather than same-day shipping. Made-to-order also means returns are limited to defective goods only.

Ready-made

Panels are pre-sewn at standard sizes and shipped from stock. Ready-made ships fast (1 to 3 days) and costs less, but width and drop are locked to standard tiers. Two Pages does not sell ready-made curtains. Big-box stores and mass retailers do.

Memory training

A post-production process where the finished panel is folded, steamed, and wrapped so pleats hold uniform shape from day one. Two Pages offers memory training as an add-on. It adds 5 to 7 days to lead time and roughly $20 to $40 per panel. Owners who skip it typically pleat-train manually over 2 to 4 weeks after unpacking.

Lead time

The number of business days between order confirmation and package dispatch. Two Pages standard lead time is 10 to 12 days. Memory training adds 5 to 7 days. Lead time is not shipping delay, it is production time, and it appears on the checkout screen before payment.

OEKO-TEX Standard 100

A textile certification confirming every component of the fabric (yarn, dye, finish, thread) has been tested against over 350 substances harmful to health. Two Pages linings and most fabric collections carry this certification. Confirmed against the OEKO-TEX Standard 100 registry. It matters most for nurseries, kids rooms, and bedding-adjacent installs.

Swatch booklet

A sample set of small fabric squares showing every colorway in a collection. The Two Pages Liz Linen booklet ships for $3.99 and covers all 38 colorways. Ordering a booklet before configuring a full custom order avoids dye lot surprises and lets the fabric hand match the room in real light.

Configurator

The online form that maps glossary vocabulary to real product fields: rod width, finished drop, header style, fullness ratio, lining, memory training, colorway. The Two Pages configurator on every product page walks buyers through these fields in order and returns a final price at the end.

FAQ

What is GSM in curtains?

GSM stands for grams per square meter, the standard textile weight measurement. Under 100 gsm reads as sheer, 100 to 160 as light drapery, 160 to 250 as mid-weight, 250 to 400 as heavyweight (Two Pages Liz Linen sits at 350 gsm), 400+ as blackout composite. Higher GSM improves drape body and thermal behavior but lifts shipping cost and forces sturdier hardware.

What is a curtain drop?

Drop is the finished vertical panel length, measured from the top of the header ring, grommet, or hook to the bottom hem. It is the second most-used input on any configurator after rod width. Standard drops follow the 4 conventions: sill length, apron length, floor kiss (1/2 inch above floor), puddle (2 to 6 inches on floor).

What does 2x fullness mean?

Fullness ratio is the multiplier between rod width and total flat panel width. 2x fullness means a 60 inch rod carries 120 inches of flat panel combined, so the drape reads tailored and pleated. Pinch pleat and grommet default to 2x. Sheers push to 2.5x, luxury drape reaches 3x, flat rod pocket stays at 1.5x.

What is memory training on curtains?

Memory training is a post-production process where the finished panel is folded, steamed, and wrapped so pleats hold uniform shape from day one. Two Pages offers it as an add-on. It adds 5 to 7 days to lead time and roughly $20 to $40 per panel. Owners who skip it typically pleat-train manually over 2 to 4 weeks after unpacking.

What is the difference between blackout and room-darkening curtains?

Blackout means 100 percent light block, achieved with a coated multi-layer lining or a blackout composite fabric. Room-darkening blocks 85 to 95 percent and lets a faint outline through around the panel edges. Blackout is the only spec that reads truly dark at 7am in a south-facing bedroom. Room-darkening is enough for living rooms, dining, and offices.

What is a pinch pleat?

Pinch pleat is a header style where the top of the panel is folded and stitched into 2, 3, or 4 finger pleats spaced every 4 to 6 inches. It carries built-in 2x fullness, hangs on drapery hooks and rings, and produces the classic tailored drapery look. Two Pages Liz Linen ships with a triple pinch pleat header as default configuration.

What is a ripple fold curtain?

Ripple fold is a track-based header style where snap tape carriers on a ceiling or wall track produce a continuous S-wave drape at 2.2x fullness. It reads architectural and clean, is common in hotels, offices, and modern residential, and requires a track system rather than a standard rod. Two Pages offers ripple fold across several collections.

What is OEKO-TEX Standard 100?

OEKO-TEX Standard 100 is a textile certification confirming every component of the fabric (yarn, dye, finish, thread) has been tested against over 350 substances harmful to health. Two Pages linings and most fabric collections carry this certification. It matters most for nurseries, kids rooms, and bedding-adjacent installs where skin contact is frequent.

One Reference. One Configurator. One Guide.

Sixty terms, seven clusters, one page. The glossary is the entry, the configurator is the exit, and the complete linen curtains guide is the middle: how every term here plays out across a real collection at $59.99 a panel, 38 colors, 350 gsm, pinch pleat by default, memory training optional.