Definition of dog:
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"
a dull unattractive unpleasant girl or woman; "she got a reputation as a frump"; "she's a real dog"
informal term for a man; "you lucky dog"
someone who is morally reprehensible; "you dirty dog"
a smooth-textured sausage of minced beef or pork usually smoked; often served on a bread roll
a hinged catch that fits into a notch of a ratchet to move a wheel forward or prevent it from moving backward
metal supports for logs in a fireplace; "the andirons were too hot to touch"
go after with the intent to catch; "The policeman chased the mugger down the alley"; "the dog chased the rabbit"