1. Capacity to endure pain or hardship.
  2. Sympathy or indulgence for beliefs or practices differing from or conflicting with one’s own.
  3. The act of allowing something.
  4. The allowable deviation from a standard.
  5. The capacity of the body to endure or become less responsive to a substance (such as a drug) or a physiological insult especially with repeated use or exposure.
  6. Relative capacity of an organism to grow or thrive when subjected to an unfavorable environmental factor.

The emotion of Tolerance is found in the Lung meridian in the Metal element.

Definition from Dictionary by Merriam-Webster.