time-ball vs orb

time-ball and orb both are nouns.

Word	Noun	Adjective	Verb	Adverb
time-ball	Yes	No	No	No
orb	Yes	No	Yes	No

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

time-ball: a ball that slides down a staff to show a fixed time; especially at an observatory
orb: an object with a spherical shape

Other hypernyms of time-ball include ball, globe.

time-ball (noun)	orb (noun)
a ball that slides down a staff to show a fixed time; especially at an observatory	the ball-shaped capsule containing the vertebrate eye
	an object with a spherical shape

time-ball (verb)	orb (verb)
	move in an orbit