n.1.A key for opening more locks than one; a master key.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
John's pass-key was a recent privilege; this was the first time it had been used; and, oh!
It's important to remember it because it's your pass-key to independence and empowerment.
Hume considers sympathy to be a psychological pass-key that allows human beings, despite their incorrigible selfishness, to enter into this impartial standpoint (p.