Like a frame of snooker? (10)
I believe the answer is:
triangular
'like' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
'a frame of snooker?' is the wordplay.
I cannot really understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for triangular that I've seen before include "involving three people?" , "Three-sided" .)