ball vs time-ball

ball and time-ball both are nouns.

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

As nouns, time-ball is a hyponym of ball; that is, time-ball is a word with a more specific, narrower meaning than ball:

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

Other hyponyms of ball include crystal ball, camphor ball, mothball, fireball, fireball, globule, spherule, pellet, bolus.

ball (noun)	time-ball (noun)
a pitch that is not in the strike zone	a ball that slides down a staff to show a fixed time; especially at an observatory
a ball game played with a bat and ball between two teams of nine players; teams take turns at bat trying to score runs
round object that is hit or thrown or kicked in games
a spherical object used as a plaything
a solid projectile that is shot by a musket
a more or less rounded anatomical body or mass
one of the two male reproductive glands that produce spermatozoa and secrete androgens
a lavish dance requiring formal attire
a compact mass
an object with a spherical shape

ball (verb)	time-ball (verb)
form into a ball by winding or rolling
to live very well