b vs square measure

b and square measure both are nouns.

Word	Noun	Adjective	Verb	Adverb
b	Yes	No	No	No
square measure	Yes	No	No	No

As nouns, square measure is a hypernym of b; that is, square measure is a word with a broader meaning than b:

b: (physics) a unit of nuclear cross section; the effective circular area that one particle presents to another as a target for an encounter
square measure: a system of units used to measure areas

Other hypernyms of b include area unit.

b (noun)	square measure (noun)
the 2nd letter of the Roman alphabet	a system of units used to measure areas
(physics) a unit of nuclear cross section; the effective circular area that one particle presents to another as a target for an encounter