- Music. the note or tone on which a key or system of tones is founded; the tonic.
- the main idea or central principle of a speech, program, thought, action, etc.
- the policy line to be followed, as by a party in a political campaign, that is set forth authoritatively in advance by an address or other formal announcement.
- keynote address.
verb (used with object), key·not·ed, key·not·ing.
- to announce the policy of (a political party, campaign, assembly, etc.); deliver a keynote address at: The governor will keynote the convention.
- to serve as the keynote for.
- Music. to give the keynote of.
verb (used without object), key·not·ed, key·not·ing.
- to provide a keynote, especially a keynote address: He refused an invitation to keynote.
- a central or determining principle in a speech, literary work, etc
- (as modifier)a keynote speech
- the note upon which a scale or key is based; tonic
- to deliver a keynote address to (a political convention, etc)
- to outline (political issues, policy, etc) in or as in a keynote address
also key-note, “lowest note of a musical scale, basis of a scale,” 1776, from key (n.1) in sense of “musical scale” + note (n.). Figurative sense of “leading idea” is from 1783; keynote address is 1905, American English.