piece vs segment

piece and segment both are nouns.

Word	Noun	Adjective	Verb	Adverb
piece	Yes	No	Yes	No
segment	Yes	No	Yes	No

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

Other hyponyms of piece include body part, corpus, acicula, base, corner, craton, cutting, fragment, hunk, lump, nub, stub, slice, strip, world.

piece (noun)	segment (noun)
a separate part of a whole	one of several parts or pieces that fit with others to constitute a whole object
game equipment consisting of an object used in playing certain board games	one of the parts into which something naturally divides
a portable gun
a work of art of some artistic value
an item that is an instance of some type
a distance
a musical work that has been created
an artistic or literary composition
an instance of some kind
a serving that has been cut from a larger portion
a portion of a natural object
a share of something
a period of indeterminate length (usually short) marked by some action or condition

piece (verb)	segment (verb)
repair by adding pieces	divide into segments
eat intermittently; take small bites of	divide or split up
join during spinning
to join or unite the pieces of
create by putting components or members together