The most common and most likely answer to this crossword clue is the 6 letter word CHAISE
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The straight part
We know that "lounge seat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lounge seat = chaise.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 CHAISE mean?
CHAISE noun- An open, horse-drawn carriage for one or two people, usually with one horse and two wheels.
- A chaise longue.
- A post chaise.