1. the tonic of a musical key.
2. A prime underlying element or theme: "the keynote of the revolution settlement was personal freedom under the law” ( G.M. Trevelyan).
3. to give or set the keynote of.
4. informal to give a keynote address at: keynoted the press luncheon.

1. the note on which a musical key is based.
2. the main theme of a speech, a written work, or a conference.
3. A speech that sets the main theme of a conference or other gathering; a keynote speech or keynote address.
4. to deliver a speech that sets the main theme of a conference or other gathering.

1. the tonic or first tone of the scale in which a piece or passage is written; the fundamental tone of the chord, to which all the modulations of the piece are referred; -- called also key tone.
2. the fundamental fact or idea; that which gives the key.

1. in music, the tone on which a key (tonality) is founded; a tonic. see
2. A central principle or idea; the pivotal point in a system, a composition, or a course of action; a controlling thought.

1. give the keynote address to (an audience)
2. (music) the first note of a diatonic scale
3. a fundamental or central idea
4. set the keynote of
5. the principal theme in a speech or literary work