mucus

Snot, that wonderful stuff your respiratory system uses to trap yucky bacteria and molds so that they can be coughed or sneezed out. It's also a good indicator of health, as if one's snot is green or white or yellow or any other strong color it means they likely have an infection.

Mu"cus (?), n. [L. mucus, muccus; cf. mucere 8be moldy or musty, Gr. mucus, and Skr. muc to release. Cf. Match for striking fire, Moist, Mucilage.]

1. Physiol.

A viscid fluid secreted by mucous membranes, which it serves to moisten and protect. It covers the lining membranes of all the cavities which open externally, such as those of the mouth, nose, lungs, intestinal canal, urinary passages, etc.

2. Physiol.

Any other animal fluid of a viscid quality, as the synovial fluid, which lubricates the cavities of the joints; -- improperly so used.

3. Bot.

A gelatinous or slimy substance found in certain algae and other plants.

© Webster 1913.