Stedman's also has mucus blanket and mucus impaction. How are those different from "mucous plug" or "mucous discharge"? I think "mucus impaction" and "mucous plug" are especially similar.Dorland's has cervical mucus, mucus extravasation phenomenon, mucus retention cyst, and sperm-cervical mucus contact test but a host of mucous phrases.
Interestingly, I didn't see mucus fistula (although I could have missed it) in either reference.
I can see some logic to Dorland's use of mucus in the phrases above but no logic to the distinctions made by Stedman's. I'd use mucous in all adjectival senses and mucus only when you are talking about the slimy icky stuff.
So, mucous membranes (the membranes secrete mucus but are not made of mucus) but mucus impaction (a wad of mucus), mucus plug (a plug made of mucus), mucus discharge (it's running out the nose or cervix), mucus blanket (a blanket of mucus), and mucus fistuula (a tract through which mucus passes). I would consider all of these compound nouns.
However, as many references as you consult, that's how many opinions you'll get on this one. It's pretty much a subjective decision. The above are just my opinion and my distinctions.
[ 02-04-2004: Message edited by: ebadrake ]
[ 02-04-2004: Message edited by: ebadrake ]