(1):

A proposal; an offer; a proposition formally submitted for consideration, acceptance, or rejection.

(2):

A composition, for a full orchestra, designed as an introduction to an oratorio, opera, or ballet, or as an independent piece; - called in the latter case a concert overture.

(3):

Disclosure; discovery; revelation.

(4):

(v. t.) To make an overture to; as, to overture a religious body on some subject.

(5):

An opening or aperture; a recess; a recess; a chamber.