BCSRA British Columbia Shorthand Reporters Association

Yes, there is a difference, beyond spelling, between mucus and mucous.  I have to look it up every time because I always forget which is which!

Mucous:

Pertaining to mucus, a thick fluid produced by the lining of some tissues of the body.

"Mucus" without an "o" is the Latin noun for "a slimy semifluid discharge from the nose." "Mucous" with an "o" is the corresponding adjective.