square metre vs square measure

square metre and square measure both are nouns.

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

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

square metre: a unit of measurement for area, defined as the area of a square with sides of exactly 1 metre; a centiare is 1/100th of an are
square measure: a system of units used to measure areas

Other hypernyms of square metre include area unit.

square metre (noun)	square measure (noun)
a unit of measurement for area, defined as the area of a square with sides of exactly 1 metre; a centiare is 1/100th of an are	a system of units used to measure areas