1. The manner or disposition of a humorist; humorousness.
2. In medicine, humor refers to a fluid (or semifluid) substance.

As such, the aqueous humor is the fluid normally present in the front and rear chambers of the eye.

The humors were part of an ancient theory that held that health came from balance between the bodily liquids. These liquids were termed humors. Disease arose when imbalance occurred between the humors.

The humors were:

• Phlegm (water).
• Blood
• Gall (black bile thought to be secreted by the kidneys and spleen).
• Choler (yellow bile secreted by the liver).

The humoral theory (also called humoralism was devised well before Hippocrates (c.460-c.375 BC). It was not definitively demolished until Rudolf Virchow published his formative book, Cellularpathologie, in 1858, which laid out the cellular basis of pathology.

Pathology now rests on a cellular and molecular foundation. The humors have been dispelled, except for the aqueous humor (and its related elements).