'Overture' is Latin for 'an opening' — from 'aperire' (to open). The musical sense came in the 1600s.
An orchestral piece at the beginning of an opera, oratorio, or suite; an introduction or preliminary to something; (usually plural) an approach or proposal made to someone.
From Old French 'overture' (opening, aperture), from 'ovrir' (to open), from Vulgar Latin *operire / *aperire variant, ultimately from Latin 'aperire' (to open, uncover, lay bare), from PIE *h₂ep- (away, off) + *wer- (to cover, shut — the same root as Latin 'operire', to cover, and English 'weir' and 'warn'). An overture is therefore literally 'an opening' — an act of uncovering or exposing what was closed. In musical contexts (entering English from French in the 17th century), an overture was the instrumental opening piece that 'opened' the