The most common and most likely answer to this crossword clue is the 4 letter word SOFA
I've seen this crossword clue in The Times
S
O
F
A
More clues leading to the result SOFA
- Seat that’s long yet slightly short
- Some works of art in Chesterfield
- Capital forfeits one seat
- Furniture up till now not quite complete
- Two notes can get you a piece of furniture
- Seat, until now, short
- Wide seat in stalls of auditorium
- Capital expels one Ottoman bearing arms?
- Very plump bottom goes on this?
- Not quite up to moment for a place to sit
Buddy explains!

The straight part
We know that "Seat that’s long" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case seat that’s long = sofa.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SOFA mean?
SOFA noun- A raised area of a building's floor, usually covered with carpeting, used for sitting.
- (furniture) An upholstered seat with a raised back and one or two raised ends, long enough to comfortably accommodate two or more people.
- To furnish with one or more sofas.
- To seat or lay down on a sofa.