Overture

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late Middle English (in the sense ‘aperture’): from Old French, from Latin apertura ‘aperture’.

wiktionary

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From Middle English overture, from Anglo-Norman, Middle French overture, from Old French overture. Doublet of aperture.

etymonline

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overture (n.)

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.