(kē) noun
1. A detachable instrument for turning the catch or bolt of a lock forwards or backwards in order to lock or unlock.
2. An instrument for holding and turning a screw, nut, valve, or the like, as for winding a clock.
3. Anything serving to disclose, open, or solve something.
4. Something that opens or prepares a way.
5. A gloss, table, or group of notes interpreting certain symbols, ciphers, problems, etc.
6. Any one of the finger levers in typewriters, typesetting machines, etc.
7. Electr. A circuit–breaker or –opener operated by the fingers, as in a telegraph–sending apparatus.
8. Music a In musical instruments, a lever to be pressed by the finger. b A system of tones, according to which a piece of music is written, in which all the notes of a scale bear a definite and recognized relationship to some particular note (the keynote or tonic): the key of C.
9. Tone or pitch of the voice.
10. Tone or style of expression.
11. Mech. a A wedge, cotter, bolt, or pin used to secure various parts together. b One of various implements, as a tightening wedge, for fixing a collar to a shaft.
12. Archit. A keystone (def. 1).
13. In building, any special surfacing or surface for holding plaster in place.
14. The roughness on the unfinished face of a veneer giving stronger adherence to the glue.
15. Bot. A key fruit; samara.
—v.t.
1. To fasten with or as with a key.
2. To wedge tightly or support firmly with a key, wedge, etc.
3. To complete (an arch) by adding the keystone.
4. To provide with keys.
5. Music To regulate the pitch or tone of.
—to key up
1. To raise the pitch of.
2. To cause excitement, anticipation, etc., in.
—adjective Of chief or decisive importance: a key position. ♦ Homophone: quay. [OE cœg]

(kē) noun
A low island, especially one of coral, along a coast: usually cay in the Gulf of Mexico and the West Indies: rarely kay. ♦ Homophone: quay. [Var. of CAY]

(kē), Francis Scott,
1780?–1843, American lawyer; wrote The Star–Spangled Banner.