Wordnet 3.0
NOUN (1)
1. 
 offspring of a coyote and a dog; 
The Collaborative International Dictionary of English v.0.48:
coydog \coydog\ n.
   the offspring of a coyote and a dog.
   Syn: coy-dog.
        [WordNet 1.5]
WordNet (r) 3.0 (2006):
coydog
    n 1: offspring of a coyote and a dog