What is the meaning of Overture?

An opening; a recess or chamber.

Disclosure; discovery; revelation.

An approach or proposal made to initiate communication, establish a relationship etc.

A motion placed before a legislative body, such as the General Assembly of the Church of Scotland.

A musical introduction to a longer piece of music or a dramatic work (such as a play, an opera, or a motion picture).

A medley of themes from a larger work, such as an opera or musical, typically played at the beginning but sometimes played at any part of the work or performed as a standalone piece.

To make overtures; to approach with a proposal.

Overt, that is, disclosed.

an opening

Source: wiktionary.org