1.metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated

2.something crucial for explaining;

the key to development is economic integration

3.pitch of the voice;

he spoke in a low key

4.any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music

5.a kilogram of a narcotic drug;

they were carrying two keys of heroin

6.a winged often one-seed indehiscent fruit as of the ash or elm or maple

7.a coral reef off the southern coast of Florida

8.(basketball) a space (including the foul line) in front of the basket at each end of a basketball court; usually painted a different color from the rest of the court;

he hit a jump shot from the top of the key

9.a list of answers to a test;

some students had stolen the key to the final exam

10. a list of words or phrases that explain symbols or abbreviations

11. a generic term for any device whose possession entitles the holder to a means of access;

a safe-deposit box usually requires two keys to open it

12. mechanical device used to wind another device that is driven by a spring (as a clock)

13. the central building block at the top of an arch or vault

14. a lever that actuates a mechanism when depressed

15.serving as an essential component;

a cardinal rule

16.effective; producing a desired effect;

the operative word