A football side? (4)
I believe the answer is:
wing
This clue might be a double definition.
'a football' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'side?' is the second definition.
(as in left and right wings)
Can you help me to learn more?
(Other definitions for wing that I've seen before include "Organ of flight" , "Take . . . . to fly away (4)" , "Wound superficially; part of large house" , "Appendage aiding flight" , "Slightly wound attacker" .)