A stake in a giant enterprise (4)
I believe the answer is:
ante
'a stake' is the definition.
(stake in poker)
'in a giant enterprise' is the wordplay.
'in' says the answer is hidden in the clue.
'ANTE' is hidden within 'giant enterprise'.
(Other definitions for ante that I've seen before include "Pay" , "Opening bet" , "Stake; before (Lat.)" , "Hoofed mammal" , "Money for poker" .)