late 13c. entren, "enter into a place or a situation; join a group or society" (trans.); early 14c., "make one's entrance" (intrans.), from Old French entrer "enter, go in; enter upon, assume; initiate," from Latin intrare "to go into, enter" (source of Spanish entrar, Italian entrare), from intra "within," related to inter (prep., adv.) "among, between," from PIE *enter "between, among," comparative of root *en "in."

Transitive and intransitive in Latin; in French intransitive only. From c. 1300 in English as "join or engage in: (an activity);" late 14c. as "penetrate," also "have sexual intercourse" (with a woman);" also "make an entry in a record or list," also "assume the duties" (of office, etc.). Related: Entered; entering.

mid-15c., reentren, "to enter (a place) again or anew," from re-, denoting "repetition of an action," + enter. By 1838 in reference to an account or record. Related: Re-entered; re-entering.

1520s, "act of entering," from French entrance, from entrer (see enter). Sense of "door, gate" first recorded in English 1530s. Meaning "a coming of an actor upon the stage" is from c. 1600.

1630s, "one who enters, a beginner" (of professions, etc.); from French entrant, present participle of entrer (see enter). From 1838 with reference to one who enters a contest. As an adjective from 1630s.

c. 1300, "act or fact of physically entering; place of entrance, means of entering a building; opportunity or right of entering; initiation or beginning of an action;" from Old French entree "entry, entrance" (12c.), noun use of fem. past participle of entrer "to enter" (see enter). Meaning "that which is entered or set down (in a book, list, etc.)" is from c. 1500.

Proto-Indo-European root meaning "in."

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."

"combine again, enter into a new combination," 1630s, from re- + combine (v.). Related: Recombined; recombining.

"to enter into a formal agreement or contract," c. 1300, from covenant (n.). Related: Covenanted; covenanting. Also see covenanter.

"enter in a hostile manner," late 15c., from Latin invadere "to go, come, or get into; enter violently, penetrate into as an enemy, assail, assault, make an attack on," from in- "in" (from PIE root *en "in") + vadere "go, walk" (see vamoose). Compare evade. Related: invaded; invading.

"enter a period of stability or stagnation, cease to rise," 1952, from plateau (n.). Related: Plateaued; plateauing.