parallelogram vs quadrilateral

parallelogram and quadrilateral both are nouns.

Word	Noun	Adjective	Verb	Adverb
parallelogram	Yes	No	No	No
quadrilateral	Yes	Yes	No	No

As nouns, quadrilateral is a hypernym of parallelogram; that is, quadrilateral is a word with a broader meaning than parallelogram:

parallelogram: a quadrilateral whose opposite sides are both parallel and equal in length
quadrilateral: a four-sided polygon

Other hypernyms of parallelogram include quadrangle, tetragon.

parallelogram (noun)	quadrilateral (noun)
a quadrilateral whose opposite sides are both parallel and equal in length	a four-sided polygon

parallelogram (adjective)	quadrilateral (adjective)
	having four sides