Keying

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).

In the sociology of Erving Goffman, an action or utterance that signals the meaning of interaction to participants.

The input of text or data by means of a keyboard.

A form of vandalism performed by scratching paint with a key