Proto-Indo-European root meaning "to flow, run."

It forms all or part of: derive; ember-days; rennet (n.1); Rhine; rialto; rill; rio; rival; rivulet; run; runnel.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit rinati "causes to flow," ritih "stream, course;" Latin rivus "stream;" Old Church Slavonic reka "river;" Middle Irish rian "river, way;" Gothic rinnan "run, flow," rinno "brook;" Middle Low German ride "brook;" Old English riþ "stream;" Old English rinnan, Old Norse rinna "to run," Dutch ril "running stream."

1856, from home (n.) + run (n.).

also long-run, "ultimate outcome," 1620s, from long (adj.) + run (n.); the notion is "when events have run their course," as in the phrase in the long run "after a long course of experience." As an adjective from 1804.

"course a river shapes through a landscape," 1939, coined by Joyce; see river (n.) + run (n.).

"rivulet, small stream of water," 1570s (Hakluyt), an alteration (by influence of run) of Middle English ryneil, from Old English rinelle, rynel, a diminutive with -el (2) + ryne "a stream" (see run (n.)).

"ordinary, unspectacular," 1922, a figurative use of a commercial phrase attested by 1909 in reference to material yielded by a mill (n.1), etc., before sorting for quality (compare common run "usual, ordinary type," from 1712). From run (n.) on the notion of "a continuous stretch of grinding."

1896, originally in reference to horse-races, from the verbal phrase, from also + past tense of run (v.). Probably from the wording of the listings given to non-placing horses in race results.

1940, in reference to military raids, etc., from hit (v.) + run (v.). As a noun phrase, Hit and run is from 1899 as a baseball play, 1924 as a driver failing to stop at an automobile accident he caused.

1530s, "stimulate to action, rouse, incite," from Latin irritatus, past participle of irritare "excite, provoke, annoy;" according to de Vaan, probably a verb from Proto-Italic *rito- "stirred," from the same PIE root that produced English run (v.). Meaning "annoy, make impatient" in English is from 1590s. The earlier verb in English was irrite (mid-15c.), from Old French irriter. Related: Irritated; irritating.

1943, of theatrical productions, from long (adv.) + present participle of run (v.). Related: Longest-running.