\Mu"cin\ (m[=u]"s[i^]n), n. [From {Mucus}.]
1. (Bot. Chem.) See {Mucedin}. [Obs.]
2. (Physiol. Chem.) An albuminoid substance which is
   contained in mucus, and gives to the latter secretion its
   peculiar ropy character. It is found in all the secretions
   from mucous glands, and also between the fibers of
   connective tissue, as in tendons. See Illust. of
   {Demilune}.