"property of being measurable," 1690s; see measurable + -ity. The earlier word was measurableness.
Entries linking to measurability
measurable adj.
c. 1300, "moderate, modest, discreet" (a sense now obsolete), from Old French mesurable "restrained, moderate, sensible; restricted," from Late Latin mensurabilis, from mensurare "to measure," from Latin mensura "a measuring, a measurement; thing to measure by," from mensus, past participle of metiri "to measure," from PIE root *me- (2) "to measure." Meaning "that can be measured" is from mid-14c. Related: Measurably.
-ity
word-forming element making abstract nouns from adjectives and meaning "condition or quality of being ______," from Middle English -ite, from Old French -ete (Modern French -ité) and directly from Latin -itatem (nominative -itas), suffix denoting state or condition, composed of -i- (from the stem or else a connective) + the common abstract suffix -tas (see -ty (2)).
Roughly, the word in -ity usually means the quality of being what the adjective describes, or concretely an instance of the quality, or collectively all the instances; & the word in -ism means the disposition, or collectively all those who feel it. [Fowler]