N American reindeer (7)
I believe the answer is:
caribou
'n american reindeer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for caribou that I've seen before include "Ruminant" , "Reindeer of North America" , "Arctic deer - a Rio cub (anag)" , "Arctic deer with large antlers" , "North American Arctic deer" .)