early 14c., "open; unfastened" (originally literal, of clothing, a book, etc.; this sense is now obsolete), from Old French overt (Modern French ouvert), past participle of ovrir "to open," from Latin aperire "to open, uncover," from PIE compound *ap-wer-yo- from *ap- "off, away" (see apo-) + root *wer- (4) "to cover." Compare Latin operire "to cover," from the same root with PIE prefix *op- "over;" and Lithuanian atverti "open," užverti "shut." The meaning "clear, open or plain to view, manifest, revealed" is from late 14c.

"in an overt manner," early 14c., from overt + -ly (2).

mid-13c., "an opening, an aperture;" early 15c. as "an introductory proposal, something offered to open the way to some conclusion," from Old French overture "opening; proposal" (Modern French ouverture), from Latin apertura "opening," from aperire "to open, uncover" (see overt).

The orchestral sense of "a movement serving as a prelude or introduction to an extended work" in English is recorded from 1660s.

mid-13c., "evident, unconcealed, manifest, apparent to the eye;" early 14c., "attractive, comely, of good appearance," shortened form of Middle English apert "open, frank," from Old French apert, from Latin apertus, past participle of aperire "to open" (see overt). Sense of "saucy, impudent" is recorded from late 14c. Less pejorative meaning "lively, brisk, in good spirits" (c. 1500) survives in U.S. dialectal peart (with Middle English alternative spelling). Related: Pertly; pertness.

Proto-Indo-European root meaning "to cover."

It forms all or part of: aperitif; apertive; aperture; barbican; cover; covert; curfew; discover; garage; garment; garnish; garret; garrison; guarantee; guaranty; kerchief; landwehr; operculum; overt; overture; pert; warn; warrant; warrantee; warranty; warren; wat; Wehrmacht; weir.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit vatah "enclosure," vrnoti "covers, wraps, shuts;" Lithuanian užveriu, užverti "to shut, to close;" Old Persian *pari-varaka "protective;" Latin (op)erire "to cover," (ap)erire "open, uncover" (with ap- "off, away"); Old Church Slavonic vora "sealed, closed," vreti "shut;" Old Irish feronn "field," properly "enclosed land;" Old English wer "dam, fence, enclosure," German Wehr "defense, protection," Gothic warjan "to defend, protect."

early 15c., "overt;" by 1590s as "situated or lying outside," from Latin externus "outside, outward" (from exterus; see exterior) + -al (1). This version won out over exterial. Related: Externally.

1846, "time above the regular hours of work, time during which one works beyond the regular hours," from over- + time (n.). In reference to the pay given for this by 1916. Sporting sense first attested 1921, in an ice hockey context.