One may be seen kissing others in the hall (8,4)
I believe the answer is:
billiard ball
'hall' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for billiard ball that I've seen before include "Object to pot" , "Sphere to be pocketed?" , "One of three in game, red, white or spotted" .)