Openings for one from Stone Age (5)
I believe the answer is:
gates
'openings' is the definition.
(I've seen this in another clue)
'one from stone age' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is present in the answer.
'from' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
The remaining letters 'gts' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for gates that I've seen before include "Entrance (to Microsoft?)" , "Movable barriers in fence or wall" , "Billionaire computer entrepreneur" , "admission?" , "Stage is set for them to open and close" .)