The most common and most likely answer to this crossword clue is the 4 letter word TORR
T
O
R
R
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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 TORR mean?
TORR noun- A unit of pressure that is equal to approximately 0.001316 atmospheres or 133.3 pascals.