Key
/kiː/
Last Updated: January 2, 2026 at 12:30 PM
Scrabble:10 ptsWWF:9 pts3 letters
Definition of Key
noun
- An object designed to open and close a lock.
- An object designed to fit between two other objects (such as a shaft and a wheel) in a mechanism and maintain their relative orientation.
- A crucial step or requirement.
"The key to solving this problem is persistence."
- A guide explaining the symbols or terminology of a map or chart; a legend.
"The key says that A stands for the accounting department."
- A guide to the correct answers of a worksheet or test.
"Some students cheated by using the answer key."
verb
- To fit (a lock) with a key.
- To fit (pieces of a mechanical assembly) with a key to maintain the orientation between them.
- To mark or indicate with a symbol indicating membership in a class.
- (telegraphy and radio telegraphy) To depress (a telegraph key).
- To operate (the transmitter switch of a two-way radio).
adjective
- Indispensable, supremely important.
"He is the key player on his soccer team."
- Important, salient.
"She makes several key points."