prism vs erecting prism

prism and erecting prism both are nouns.

Word	Noun	Adjective	Verb	Adverb
prism	Yes	No	No	No
erecting prism	Yes	No	No	No

As nouns, erecting prism is a hyponym of prism; that is, erecting prism is a word with a more specific, narrower meaning than prism:

prism: optical device having a triangular shape and made of glass or quartz; used to deviate a beam or invert an image
erecting prism: a right-angled optical prism used to turn an inverted image upright

prism (noun)	erecting prism (noun)
optical device having a triangular shape and made of glass or quartz; used to deviate a beam or invert an image	a right-angled optical prism used to turn an inverted image upright
a polyhedron with two congruent and parallel faces (the bases) and whose lateral faces are parallelograms