Wordnet 3.0
NOUN (1)
1. 
 a member of the genus Canis (probably descended from the common wolf) that has been domesticated by man since prehistoric times; 
 occurs in many breeds; 
- Example: "the dog barked all night"[syn: dog, domestic dog, Canis familiaris]
WordNet (r) 3.0 (2006):
domestic dog
    n 1: a member of the genus Canis (probably descended from the
         common wolf) that has been domesticated by man since
         prehistoric times; occurs in many breeds; "the dog barked
         all night" [syn: dog, domestic dog, Canis familiaris]