Entries linking to internality
Meaning "situated within" is from 1590s. Meaning "of or pertaining to the domestic affairs of a country (as in internal revenue) is from 1795; the notion is "pertaining to the subject itself; independent of others." Internal-combustion in reference to an engine in which fuel is burned inside it, is from 1884. Related: Internally.
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]