Parts of a Sofa – Labeled Diagram, Outside and Inside

All 12 parts on the diagram

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The sofa 6

Seat cushion A loose pad you sit on. It may be dense foam wrapped in a softer fiber filling.
Back cushion A loose pad you lean against. It rests on the seat cushions and against the back.
Arm A sofa has one at each end. Upholsterers name its two faces the inside arm and the outside arm.
Back The upright part behind you as you sit. Its two faces are the inside back and the outside back.
Leg Short legs lift the frame off the floor. A skirt, where a sofa has one, hangs down and hides them.
Welt A strip of the cover fabric sewn round a cord. It is used to finish a seam. Also called welting, cording or piping.

Inside the seat 6

Frame The skeleton everything else is fixed to. It is usually wood, but can be steel, plastic or laminated board.
Springs Springs under the padding give the seat its support. These are coil springs; many sofas have flat zigzag springs.
Webbing Strips stretched across the frame. They hold up the springs or the padding.
Padding The soft layer between the springs and the cover. It is made from down, feathers, foam, fabric or a mix of them.
Deck The platform under the loose seat cushions. The plain cloth that covers it is called decking.
Dust cover A thin cloth, usually black cambric, tacked under the sofa. It hides the webbing and the bottom of the frame.

How this list was compiled: Part names checked on 2026-09-30; a name is kept only when two independent sources use it. (1) Wikipedia, Couch, text only, https://en.wikipedia.org/wiki/Couch (frame, springs, padding, covering, upholstered armrests, cushions). (2) Page Parker, Upholstering for Everyone (1976), read through the Internet Archive's full-text search, https://archive.org/details/upholsteringfore0000park (seat cushion, back cushion, inside arm, outside back, deck, webbing, springs, welt, skirt, dust cover, legs, frame). (3) Clois Kicklighter, Upholstery Fundamentals (2001), read the same way, https://archive.org/details/upholsteryfundam0000kick (seat cushion, back cushion, inside arm, outside back, deck and decking, webbing, coil and sinuous springs, welt cord, skirt, dust cover of cambric, legs, frame). (4) What's What, a Visual Glossary of the Physical World (1981), read the same way, https://archive.org/details/whatswhatvisualg0000brag_z6n4 (a sofa has a back and two arms; seat cushion, armrest, welting). The three books are in copyright and were read as search snippets, not whole pages. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's product is copied and nothing is traced. Licence: own work

How it works

A sofa, or couch, is a frame, springs, padding and a cover. This drawing names the parts you can see from the front, then cuts the seat open to name the ones you cannot.

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What you can see

An arm stands at each end and the back rises behind. You sit on the seat cushions and lean on the back cushions. The cord along a cushion's edge is the welt, and short legs hold the whole sofa off the floor.

What is under the cushions

Lift a seat cushion and you are looking at the deck. Under the deck comes the padding, then the springs, which stand on webbing stretched across the wooden frame. A dust cover closes the bottom.

Welt, welting, cording and piping all name the cord along a seam.
Sofa and couch mean the same piece of furniture; a sofa for two is a loveseat.

Questions and answers

What are the parts of a sofa called?

Outside: the arms, the back, the seat cushions, the back cushions and the legs. Inside: a frame, springs and padding, with a deck under the seat cushions and a dust cover underneath.

What is the part under the sofa cushions called?

The deck. It is the platform the loose seat cushions rest on, and the plain cloth that covers it is called decking or platform cloth.

What is the black fabric under a sofa called?

A dust cover. It is a thin cloth, usually black cambric, fixed under the sofa to hide the webbing and the bottom of the frame.

What is inside a sofa seat?

A couch has a frame, springs, padding and covering; its frame is usually wood, the springs sit under the padding for support, and the padding is foam, down, feathers, fabric or a mix.