Mu"cin (mū"s&ibreve;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.