Overtone
The sounds produced by the division of a vibrating body into equal parts.
Overture, Overtura (It.), Ouverture (Fr.), Ouverture (Ger.). A musical prelude to an opera or oratorio. Independent compositions are also written under the name of concert overtures, generally with some descriptive title. In its highest form the overture is developed in the sonata form without repeating the first part. Many overtures are nothing but a medley of airs in various tempos.