voussoir vs building block

voussoir and building block both are nouns.

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

As nouns, building block is a hypernym of voussoir; that is, building block is a word with a broader meaning than voussoir:

voussoir: wedge-shaped stone building block used in constructing an arch or vault
building block: a block of material used in construction work

voussoir (noun)	building block (noun)
wedge-shaped stone building block used in constructing an arch or vault	a block of material used in construction work
	a single undivided natural thing occurring in the composition of something else