"quality or state of being marginal," 1849, from marginal + -ity.
Entries linking to marginality
marginal adj.
1570s, "written or printed on the margin of a page," from Medieval Latin marginalis, from Latin margo "edge, brink, border, margin" (see margin (n.)). Sense of "of little effect or importance" first recorded 1887. Related: Marginally.
-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]