tricycle vs velocipede

tricycle and velocipede both are nouns.

As nouns, tricycle and velocipede are synonyms defined as:

tricycle and velocipede: a vehicle with three wheels that is moved by foot pedals

Other synonyms of tricycle include trike.

tricycle (noun)	velocipede (noun)
a vehicle with three wheels that is moved by foot pedals	any of several early bicycles with pedals on the front wheel
	a vehicle with three wheels that is moved by foot pedals