Subsequently, much laughter is heard (5)
I believe the answer is:
after
'subsequently' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for after that I've seen before include "Looking for" , "Subsequently" , "Subsequent to" , "In pursuit of, behind" , "Coming later in time" .)