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.(noun)
source: webster1913
verb (v)
set the keynote of(verb.change)
Example: Comfort keynotes this designer's Fall collection.
source: wordnet30
give the keynote address to (an audience)(verb.communication)