What does "pun" mean?

Additional senses

1. 2.A play on words which have the same sound but different meanings; an expression in which two different applications of a word present an odd or ludicrous idea; a kind of quibble or equivocation. Addison. A better put on this word was made on the Beggar's Opera, which, it was said, made Gay rich, and Rich gay. Walpole.
2. 3.To make puns, or a pun; to use a word in a double sense, especially when the contrast of ideas is ludicrous; to play upon words; to quibble. Dryden.
3. 4.To persuade or affect by a pun. Addison.