Sense of "device that converts energy to mechanical power" is 18c.; in 19c. especially of steam engines. Middle English also had ingeny (n.) "gadget, apparatus, device," directly from Latin ingenium.
early 15c., "intellectual, talented," from Old French ingenios, engeignos"clever, ingenious" (Modern French ingénieux), from Latin ingeniosus "of good natural capacity, full of intellect, clever, gifted with genius," from ingenium "innate qualities, ability; inborn character," literally "that which is inborn," from in- "in" (from PIE root *en "in") + gignere "to beget" (from PIE *gen(e)-yo-, suffixed form of root *gene- "give birth, beget").
Sense of "skillful, crafty, clever at contrivance" first recorded 1540s; earlier in this sense was Middle English enginous (mid-14c.), from Old French engeignos. Middle English also had engineful "skillful (in war)" (c. 1300). By a direct path, Latin ingenium produced Middle English ingeny "intellectual capacity, cleverness" (early 15c.), but this is obsolete. Compare engine. Related: Ingeniously; ingeniousness.
It forms all or part of: and; atoll; dysentery; embargo; embarrass; embryo; empire; employ; en- (1) "in; into;" en- (2) "near, at, in, on, within;" enclave; endo-; enema; engine; enoptomancy; enter; enteric; enteritis; entero-; entice; ento-; entrails; envoy; envy; episode; esoteric; imbroglio; immolate; immure; impede; impend; impetus; important; impostor; impresario; impromptu; in; in- (2) "into, in, on, upon;" inchoate; incite; increase; inculcate; incumbent; industry; indigence; inflict; ingenuous; ingest; inly; inmost; inn; innate; inner; innuendo; inoculate; insignia; instant; intaglio; inter-; interim; interior; intern; internal; intestine; intimate (adj.) "closely acquainted, very familiar;" intra-; intricate; intrinsic; intro-; introduce; introduction; introit; introspect; invert; mesentery.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit antara- "interior;" Greek en "in," eis "into," endon "within;" Latin in "in, into," intro "inward," intra "inside, within;" Old Irish in, Welsh yn, Old Church Slavonic on-, Old English in "in, into," inne "within, inside."
*genə-, also *gen-, Proto-Indo-European root meaning "give birth, beget," with derivatives referring to procreation and familial and tribal groups.
It forms all or part of: Antigone; autogenous; benign; cognate; congener; congenial; congenital; connate; cosmogony; cryogenic; degenerate; engender; engine; epigone; eugenics; -gen; gendarme; gender; gene; genealogy; general; generate; generation; generic; generous; genesis; -genesis; genial; -genic; genital; genitive; genius; genocide; genotype; genre; gens; gent; genteel; gentile; gentle; gentry; genuine; genus; -geny; germ; german (adj.) "of the same parents or grandparents;" germane; germinal; germinate; germination; gingerly; gonad; gono-; gonorrhea; heterogeneous; homogeneous; homogenize; homogenous; impregnate; indigenous; ingenious; ingenuous; innate; jaunty; kermes; kin; kindergarten; kindred; king; kind (n.) "class, sort, variety;" kind (adj.) "friendly, deliberately doing good to others;" Kriss Kringle; malign; miscegenation; nada; naive; nascent; natal; Natalie; nation; native; nature; nee; neonate; Noel; oncogene; ontogeny; photogenic; phylogeny; pregnant (adj.1) "with child;" primogenitor; primogeniture; progenitor; progeny; puisne; puny; renaissance; theogony; wunderkind.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit janati "begets, bears," janah "offspring, child, person," janman- "birth, origin," jatah "born;" Avestan zizanenti "they bear;" Greek gignesthai "to become, happen," genos "race, kind," gonos "birth, offspring, stock;" Latin gignere "to beget," gnasci "to be born," genus (genitive generis) "race, stock, kind; family, birth, descent, origin," genius "procreative divinity, inborn tutelary spirit, innate quality," ingenium "inborn character," possibly germen "shoot, bud, embryo, germ;" Lithuanian gentis "kinsmen;" Gothic kuni "race;" Old English cennan "beget, create," gecynd "kind, nature, race;" Old High German kind "child;" Old Irish ro-genar "I was born;" Welsh geni "to be born;" Armenian cnanim "I bear, I am born."
also Diesel, type of internal combustion engine, 1894, named for Rudolf Diesel (1858-1913), German mechanical engineer who designed this type of engine.