Head across the pond?
I believe the answer is:
loo
'head across the pond?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for loo that I've seen before include "Lavatory - old card game" , "Toilet (informal)" , "Rest room" , "WC - old card game" , "The little room - card game" .)