n. 25B6; noun
I put my key in the lock : door key, latchkey, pass key, master key.
the key to the mystery 007C; the key to success : ANSWER, clue, solution, explanation; basis, foundation, requisite, precondition, means, way, route, path, passport, secret, formula.
(Music) a minor key : TONE, pitch, timbre, tone colour.
an austerely intellectual key : STYLE, character, mood, vein, spirit, feel, feeling, flavour, quality, atmosphere.
25B6; adjective a key figure : CRUCIAL, central, essential, indispensable, pivotal, critical, dominant, vital, principal, prime, chief, major, leading, main, important, significant.
peripheral.