River goddess in Egypt (4)
I believe the answer is:
isis
This could be a double definition.
'river' is the first definition.
(term for the River Thames in Oxford)
'goddess in egypt' is the second definition.
'isis' can be an answer for 'goddess' (Egyptian god). I am not certain of the 'in egypt' bit.
Can you help me to learn more?
(Other definitions for isis that I've seen before include "water" , "Egyptian goddess of nature" , "The upper Thames" , "Egyptian deity" , "Wife of Osiris" .)