n. device used to open locks; something which allows entry; something which explains or assists in solving a problem; means to acquire or reach something; legend, list which provides decoding information; button on a keyboard; tone, note, pitch (Music)
v. lock with a key, fasten with a key; fit, adapt, adjust; tune, adjust the pitch of (Music); supply with an explanatory device; type into a computer by means of a keyboard (Computers)