The most common and most likely answer to this crossword clue is the 4 letter word RALE
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More clues leading to the result RALE
Buddy explains!
The straight part
We know that "What one hears during 20" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what one hears during 20 = rale.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 RALE mean?
RALE noun- (now chiefly in plural) An abnormal clicking, rattling or crackling sound, made by one or both lungs and heard with a stethoscope, caused by the popping open of airways collapsed by fluid or exudate, or sometimes by pulmonary edema.