mothball vs orb

mothball and orb both are nouns.

Word	Noun	Adjective	Verb	Adverb
mothball	Yes	No	Yes	No
orb	Yes	No	Yes	No

As nouns, orb is a hypernym of mothball; that is, orb is a word with a broader meaning than mothball:

mothball: a small sphere of camphor or naphthalene used to keep moths away from stored clothing
orb: an object with a spherical shape

Other hypernyms of mothball include ball, globe.

mothball (noun)	orb (noun)
a small sphere of camphor or naphthalene used to keep moths away from stored clothing	the ball-shaped capsule containing the vertebrate eye
	an object with a spherical shape

mothball (verb)	orb (verb)
put into long-term storage	move in an orbit