ptarmigan
Concise Oxford English Dictionary © 2008 Oxford University Press:
ptarmigan /ˈtɑːmɪg(ə)n/
▶noun a grouse of northern mountains and the Arctic, whose plumage is white in winter. [Lagopus mutus.]
– origin C16: from Sc. Gaelic tàrmachan; spelling influenced by Gk words starting with pt-.
'ptarmigan' also found in these Oxford entries:

