1.NounA speech that sets the main theme of a conference or other gathering; a keynote speech or keynote address.
"keynote speech; keynote speaker; deliver the keynote; She delivered the keynote address at the conference.; Innovation was the keynote of the company’s presentation."
2.NounThe main theme of a speech, a written work, or a conference.
3.NounThe note on which a musical key is based; the tonic.
4.VerbTo deliver a speech that sets the main theme of a conference or other gathering.