1590s, from total (adj.) + -ity, or from or based on French totalité, Medieval Latin totalitas. In the eclipse sense, "time of total obscuration," from 1842.
Entries linking to totality
total adj.
late 14c., from Old French total (14c.), from Medieval Latin totalis "entire, total" (as in summa totalis "sum total"), from Latin totus "all, all at once, the whole, entire, altogether," a word of unknown origin. Total war is attested from 1937 (William Shirer), in reference to a concept developed in Germany.
-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]