Key

1. n. Fig: The general pitch or tone of a sentence or utterance.
2. n. An instrument by means of which the bolt of a lock is shot or drawn; usually, a removable metal instrument fitted to the mechanism of a particular lock and operated by turning in its place.
3. n. An instrument which is turned like a key in fastening or adjusting any mechanism; as, a watch key; a bed key, etc.
4. n. That part of an instrument or machine which serves as the means of operating it; as, a telegraph key; the keys of a pianoforte, or of a typewriter.
5. n. A position or condition which affords entrance, control, pr possession, etc.; as, the key of a line of defense; the key of a country; the key of a political situation. Hence, that which serves to unlock, open, discover, or solve something unknown or difficult; as, the key to a riddle; the key to a problem.
6. n. That part of a mechanism which serves to lock up, make fast, or adjust to position.
7. n. A piece of wood used as a wedge.
8. n. The last board of a floor when laid down.
9. n. A keystone.
10. n. That part of the plastering which is forced through between the laths and holds the rest in place.
11. 1n. 1 Fig: The general pitch or tone of a sentence or utterance.
12. 1n. 1 An instrument by means of which the bolt of a lock is shot or drawn; usually, a removable metal instrument fitted to the mechanism of a particular lock and operated by turning in its place.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.