Relative across the Atlantic (5,3)
I believe the answer is:
uncle sam
This could be a double definition.
'relative' is the first definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'across the atlantic' is the second definition.
(Uncle Sam is an informal term for the USA)
(Other definitions for uncle sam that I've seen before include "The United States" , "USA personified" , "Federal government" , "America personified" , "Personification of USA" .)