The most common and most likely answer to this crossword clue is the 8 letter word OTTOMANS
I've seen this crossword clue in The Daily Telegraph
O
T
T
O
M
A
N
S
Buddy explains!

The straight part
We know that "seats" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case seats = ottomans.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 OTTOMANS mean?
OTTOMANS noun- An upholstered sofa, without arms or a back, sometimes with a compartment for storing linen, etc.
- A low stool or thick cushion used to rest the feet or as a seat.
- A fabric with a pronounced ribbed or corded effect, often made of silk or a mixture of cotton and silk-like yarns.