n. 1 a prevailing tone or idea (the keynote of the whole occasion). 2 (attrib.) intended to set the prevailing tone at a meeting or conference (keynote address). 3 Mus. the note on which a key is based.
KEYNOTE
Meaning of KEYNOTE in English
Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012