Sounds like standard shot at billiards? (6)
I believe the answer is:
cannon
'shot at billiards?' is the definition.
'cannon' can be an answer for 'shot' (I have seen 'Big shot' mean 'cannon' so perhaps 'shot' could also mean 'cannon'). I am not certain of the 'at billiards?' bit.
'sounds like standard' is the wordplay.
'sounds like' indicates a 'sounds like' (homophone) clue.
'standard' becomes 'canon' (I've seen this before).
'canon' is a homophone of 'CANNON'.
Can you help me to learn more?
(Other definitions for cannon that I've seen before include "Big gun" , "Billiard shot in which player's ball hits the two others" , "Gun - billiards' shot" , "Big shot" , "Great gun" .)