intermediate (adj.)

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.

1540s, "divide in two equal parts" (a sense now obsolete), from Latin mediatus, past participle of mediare "to halve," later, "be in the middle," from Latin medius "middle" (from PIE root *medhyo- "middle"); from 1640s as "occupy a middle place or position." Meaning "act as a mediator, intervene for the purpose of reconciliation" is from 1610s; that of "settle by mediation, harmonize, reconcile" is from 1560s, perhaps back-formations from mediation or mediator. Related: Mediated; mediates; mediating.