all-terrain bike vs bike

all-terrain bike and bike both are nouns.

Word	Noun	Adjective	Verb	Adverb
all-terrain bike	Yes	No	No	No
bike	Yes	No	Yes	No

As nouns, bike is a hypernym of all-terrain bike; that is, bike is a word with a broader meaning than all-terrain bike:

all-terrain bike: a bicycle with a sturdy frame and fat tires; originally designed for riding in mountainous country
bike: a wheeled vehicle that has two wheels and is moved by foot pedals

Other hypernyms of all-terrain bike include bicycle, cycle, wheel.

all-terrain bike (noun)	bike (noun)
a bicycle with a sturdy frame and fat tires; originally designed for riding in mountainous country	a wheeled vehicle that has two wheels and is moved by foot pedals
	a motor vehicle with two wheels and a strong frame

all-terrain bike (verb)	bike (verb)
	ride a bicycle