1. The emotion evoked by well-being, success, or good fortune or by the prospect of possessing what one desires.
  2. The expression or exhibition of such emotion.
  3. A state of happiness or felicity.
  4. A source or cause of delight.
  5. (verb) To experience great pleasure or delight.

The emotion of Joy is found in the Small Intestine meridian in the Fire element.

Definition from Dictionary by Merriam-Webster.