building block vs piece

building block and piece both are nouns.

Word	Noun	Adjective	Verb	Adverb
building block	Yes	No	No	No
piece	Yes	No	Yes	No

building block (noun)	piece (noun)
a block of material used in construction work	a separate part of a whole
a single undivided natural thing occurring in the composition of something else	game equipment consisting of an object used in playing certain board games
	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

building block (verb)	piece (verb)
	repair by adding pieces
	eat intermittently; take small bites of
	join during spinning
	to join or unite the pieces of
	create by putting components or members together