Origin and history of intertextuality

late 14c., textuel "of, pertaining to, or contained in a text," also "well-read, learned in texts," perhaps coined in Middle English or perhaps from Old French textuel; ultimately from Latin textus (see text (n.)).

The English spelling was conformed to Latin from late 15c. Related: Textually. Another adjective coined to go with text and not textile (n.) was textuary "of or pertaining to texts," also "having authority or importance" (17c.). This also was used as a noun, "one versed in Scripture or other texts," and in 18c. "one who adheres strictly to the letter of a text." The classical Latin adjectives (textilis, etc.) refer to weaving or weavers. Related: Textualist; textualism.

word-forming element used freely in English, "between, among, during," from Latin inter (prep., adv.) "among, between, betwixt, in the midst of" (also used extensively as a prefix), from PIE *enter "between, among" (source also of Sanskrit antar, Old Persian antar "among, between," Greek entera (plural) "intestines," Old Irish eter, Old Welsh ithr "among, between," Gothic undar, Old English under "under"), a comparative of root *en "in."

A living prefix in English from 15c. and used with Germanic as well as Latinate words. Spelled entre- in French; most words borrowed into English in that form were re-spelled 16c. to conform with Latin except entertain, enterprise. In Latin, spelling shifted to intel- before -l-, hence intelligence, etc.

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]