key

Definition of key

1. 1 a :  a usually metal instrument by which the bolt of a lock is turned b :  any of various devices having the form or function of such a key
2. 2 a :  a means of gaining or preventing entrance, possession, or control b :  an instrumental or deciding factor
3. 3 a :  something that gives an explanation or identification or provides a solution <the key to a riddle> b :  a list of words or phrases giving an explanation of symbols or abbreviations c :  an aid to interpretation or identification :  clue d :  an arrangement of the salient characters of a group of plants or animals or of taxa designed to facilitate identification e :  a map legend
4. 4 a (1) :  cotter pin (2) :  cotter b :  a keystone in an arch c :  a small piece of wood or metal used as a wedge or for preventing motion between parts
5. 5 a :  one of the levers of a keyboard musical instrument that actuates the mechanism and produces the tones b :  a lever that controls a vent in the side of a woodwind instrument or a valve in a brass instrument c :  a part to be depressed by a finger that serves as one unit of a keyboard
6. 6 :  samara
7. 7 :  a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic <the key of G major>
8. 8 a :  characteristic style or tone b :  the tone or pitch of a voice c :  the predominant tone of a photograph with respect to its lightness or darkness
9. 9 :  a decoration or charm resembling a key
10. 10 :  a small switch for opening or closing an electric circuit <a telegraph key>
11. 11 :  the set of instructions governing the encipherment and decipherment of messages
12. 12 :  a free-throw area in basketball

keyed play \ˈkēd\ adjective

keyless play \ˈkē-ləs\ adjective