Reference
Modular Sofa Glossary
Plain-English answers to the terms that actually change your buying decision. Each definition is written to stand on its own.
Modular sofa
A modular sofa is a seating system built from separate sections, called modules, that connect and rearrange to fit a room. Because you can add, remove or reposition pieces, the same set can become a straight sofa, an L-shape or a U-shape as your space or needs change over time.
Module
A module is a single self-contained section of a modular sofa, such as an armless seat, a corner piece or an ottoman. Modules connect to one another to build a larger sofa, and can be separated or reconfigured later without replacing the whole set.
Sectional
A sectional is a large sofa made of multiple connected sections that together form one continuous seating area, usually in an L or U shape. Every modular sofa is a kind of sectional, but not every sectional is modular; some are fixed and cannot be rearranged after delivery.
L-shaped sectional
An L-shaped sectional is a sofa that turns one corner, forming the letter L. It seats a family along two walls while leaving the room open, and suits most living rooms. The long side, called the chaise, can often be ordered on the left or right.
U-shaped sectional
A U-shaped sectional wraps three sides of a seating area, forming the letter U with two long returns and a central span. It offers the most seats for group lounging, but needs a large room. Measure carefully, as widths often exceed 120 inches.
Seat depth
Seat depth is the distance from the front edge of the seat cushion to the base of the backrest. Deeper seats, around 27 to 40 inches, let you stretch out or curl up, while shallower seats near 21 to 24 inches suit upright sitting and shorter bodies.
Sleeper / sofa bed
A sleeper, or sofa bed, is a sofa that converts into a sleeping surface for overnight guests. Designs range from fold-out mattresses to simple flip or pull-forward seats. Boneless foam styles unfold flat without a metal frame, trading a little support for lighter weight and easier setup.
Compression shipping
Compression shipping vacuum-packs foam seating into smaller boxes so a large sofa fits through standard doorways and ships more cheaply. After unboxing, the foam expands to full size over a few hours. It usually means little or no tool-based assembly, but expect a short expansion period.
Ready to use these terms? Compare exact sizes in our dimension database, or read the U-shaped vs L-shaped guide.