"state of being potential, mere being without actualization," 1620s, from potential + -ity, or else from Medieval Latin potentialitas, from potentialis.
Entries linking to potentiality
potential adj.
late 14c., "possible" (as opposed to actual), "capable of being or becoming," from Old French potenciel and directly from Medieval Latin potentialis "potential," from Latin potentia "power, might, force;" figuratively "political power, authority, influence," from potens "powerful," from potis "powerful, able, capable; possible;" of persons, "better, preferable; chief, principal; strongest, foremost," from PIE root *poti- "powerful; lord."
The noun, meaning "that which is possible, anything that may be" is attested by 1817 (Coleridge), from the adjective. Middle English had potencies (plural) "a caustic medicine" (early 15c.).
-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]