Rheums are a type of fluid that can build up in the eyes, nose, or throat, causing discomfort and irritation. There are several synonyms for rheums, including mucus, phlegm, snot, and nasal discharge. These terms are often used interchangeably to describe the same condition, but there are subtle differences in their meaning. For example, mucus refers specifically to the sticky liquid that lines the respiratory and digestive tracts, while phlegm is a thicker version of mucus that is associated with respiratory infections. Snot is a colloquial term used to describe nasal discharge, and nasal discharge can refer to any fluid that comes out of the nose.