Chihuahua is a hyponym of dog.

As nouns the difference between dog and chihuahua

is that dog is a mammal, Canis lupus familiaris, that has been domesticated for thousands of years, of highly variable appearance due to human breeding while chihuahua is alternative case form of Chihuahua.

As an acronym DOG

is digital on-screen graphic.

As a verb dog

is to pursue with the intent to catch.

As a proper noun Chihuahua is

a desert state in northwestern Mexico.