The Collaborative International Dictionary of English v.0.48:
Nucha \Nu"cha\, n.; pl. Nuchae. [LL.] (Zool.) The back or upper part of the neck; the nape. [1913 Webster]WordNet (r) 3.0 (2006):
nucha n 1: the back side of the neck [syn: nape, scruff, nucha]