Goddess of fertility (4)
I believe the answer is:
isis
'goddess of fertility' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for isis that I've seen before include "Egyptian goddess - Thames at Oxford" , "Si Si - she's an Egyption goddess" , "where one might take a punt" , "Oxford's second crew" , "Oxford's second eight" .)