Company in ancient wood? (3)
I believe the answer is:
two
'company' is the definition.
(I've seen this before)
'in ancient wood?' is the wordplay.
'in' indicates a hidden word.
'TWO' is hidden in the letters of 'ancient wood'.
(Other definitions for two that I've seen before include "prime -- that's not odd" , "Number of faces of the god Janus" , "Number in pair" , "Minimal number of partners" , "not very many" .)