Kay

1. Used to indicate acknowledgement or acceptance.

   I promise to give it back. – OK.

2. Used to introduce a sentence in order to draw attention to the importance of what is being said.

   OK, I'm thinking of a number…

3. Used in turn-taking, serving as a request to the speaker to grant the turn to the interrupter.

   You always do this to me! When we were at your mother’s, you said that… – OK, OK, …

noun

A small, low island largely made of sand or coral.

1. The name of the Latin-script letter K.
2. A kilometer.
3. A thousand of some unit (from kilo-).