ground beef vs hamburger

ground beef and hamburger both are nouns.

Word	Noun	Adjective	Verb	Adverb
ground beef	Yes	No	No	No
hamburger	Yes	No	No	No

As nouns, ground beef and hamburger are synonyms defined as:

ground beef (noun)	hamburger (noun)
beef that has been ground	beef that has been ground
	a sandwich consisting of a fried cake of minced beef served on a bun, often with other ingredients