First, go to the online Merriam-Webster Dictionary at www.m-w.com.

Second, look up the word “JOKE.” It will give you this definition:

1 a : something said or done to provoke laughter; especially : a brief oral narrative with a climactic humorous twist b (1) : the humorous or ridiculous element in something (2) : an instance of jesting : KIDDING c : PRACTICAL JOKE d : LAUGHINGSTOCK

There’s a cross-reference link to “KIDDING.” Click on that, and it takes you to this definition:

Main Entry: 2kid
Function: intransitive verb
Inflected Form(s): kid·ded; kid·ding
Date: 15th century
: to bring forth young — used of a goat or an antelope