keynote

American  

[kee-noht] / ˈkiˌnoʊt /

noun

1. Music. the note or tone on which a key or system of tones is founded; the tonic.

2. the main idea or central principle of a speech, program, thought, action, etc.

3. 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.

4. keynote address.

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verb (used with object)

keynoted, keynoting

1. to announce the policy of (a political party, campaign, assembly, etc.); deliver a keynote address at.

   The governor will keynote the convention.

2. to serve as the keynote for.

3. Music. to give the keynote of.

verb (used without object)

keynoted, keynoting

1. to provide a keynote, especially a keynote address.

   He refused an invitation to keynote.

keynote British  

/ ˈkiːˌnəʊt /

noun

1. 1. a central or determining principle in a speech, literary work, etc

   2. ( as modifier )

      a keynote speech

2. the note upon which a scale or key is based; tonic

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verb

1. to deliver a keynote address to (a political convention, etc)

2. to outline (political issues, policy, etc) in or as in a keynote address

Etymology

Origin of keynote

First recorded in 1755–65; key ¹ + note

Explanation

A keynote is "the leading note in a musical key," and that meaning has spread to include the leading theme or idea in almost anything. For example, a keynote speaker at a conference includes this central subject in her speech. You're most likely to find the word keynote followed by "speech," "address," or "speaker." The central keynote theme is often presented right at the beginning of a conference or seminar. Another meaning of keynote is "the leading note in a musical key." When you play a scale on the piano, the first, lowest, note is the keynote. This musical meaning dates from the mid-1700s, and the phrase "keynote address" was first used in 1905.

Example Sentences

After all, that’s why Siri AI was the centerpiece of its developer-conference keynote: to convince app makers that Siri will drive users to their apps, not away from them.

From The Wall Street Journal • Jun. 9, 2026

His replacement, John Ternus, did not appear as part of the main keynote presentation but was seated in the front row next to Cook at a media briefing on the company's new Siri AI features.

From BBC • Jun. 8, 2026

The world’s richest man has been invited as the keynote speaker for ASML’s private technology conference this Thursday, according to Bloomberg and other media reports.

From MarketWatch • Jun. 8, 2026

Ukrainian officials said the attack was aimed at disrupting the three-day gathering, which President Vladimir Putin will attend and make a keynote address at on Friday.

From Barron's • Jun. 3, 2026

Keynote: As a musical term, keynote identifies the “key” of a piece.

From "Music and the Child" by Natalie Sarrazin