Shag describes a rug with notably long, loose pile — often an inch or more — rather than the short, dense pile typical of most other constructions. The length of the pile is the defining feature; shag rugs are usually hand-tufted, since that construction allows the longer, looser yarn shag requires.
Why it matters to a buyer
Because long pile obscures fine detail, shag designs tend to be simple — solid colours, subtle tonal patterns, or soft abstract shapes — with the appeal resting on texture and comfort underfoot rather than intricate pattern work. Shag rugs typically need less traffic exposure to stay looking good, since loose, long pile crushes and tangles more readily than short pile.