inventory n.

early 15c., invencioun, "finding or discovering of something," from Old French invencion (13c.) and directly from Latin inventionem (nominative inventio) "faculty of invention," noun of action from past-participle stem of invenire "to come upon, find; find out; invent, discover, devise; ascertain; acquire, get, earn," from in- "in, on" (from PIE root *en "in") + venire "to come" (from a suffixed form of PIE root *gwa- "to go, come").

The sense of "thing invented" is first recorded 1510s; that of "act or process of finding out how to make or do" is from 1530s.

Invention is applied to the contrivance and production of something, often mechanical, that did not before exist, for the utilization of powers of nature long known or lately discovered by investigation. Discovery brings to light what existed before, but was not known. [Century Dictionary]

The earliest sense of the word in Middle English was "devised method of organization" (c. 1400), a sense now obsolete. The meaning "finding or discovery of something" is preserved in Invention of the Cross, Church festival (May 3) celebrating the reputed finding of the Cross of the Crucifixion by Helena, mother of Constantine, in 326 C.E. The related classical Latin word for "a device, contrivance" was inventum.

adjective and noun word-forming element, in most cases from Latin -arius, -aria, -arium "connected with, pertaining to; the man engaged in," from PIE relational adjective suffix *-yo- "of or belonging to." The neuter of the adjectives in Latin also were often used as nouns (solarium "sundial," vivarium, honorarium, etc.). It appears in words borrowed from Latin in Middle English. In later borrowings from Latin to French, it became -aire and passed into Middle English as -arie, subsequently -ary.

*gwā-, also *gwem-, Proto-Indo-European root meaning "to go, come."

It forms all or part of: acrobat; adiabatic; advent; adventitious; adventure; amphisbaena; anabasis; avenue; base (n.) "bottom of anything;" basis; become; circumvent; come; contravene; convene; convenient; convent; conventicle; convention; coven; covenant; diabetes; ecbatic; event; eventual; hyperbaton; hypnobate; intervene; intervenient; intervention; invent; invention; inventory; juggernaut; katabatic; misadventure; parvenu; prevenient; prevent; provenance; provenience; revenant; revenue; souvenir; subvention; supervene; venire; venue; welcome.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit gamati "he goes," Avestan jamaiti "goes," Tocharian kakmu "come," Lithuanian gemu, gimti "to be born," Greek bainein "to go, walk, step," Latin venire "to come," Old English cuman "come, approach," German kommen, Gothic qiman.