Mu"ci*lage (?), n. [F., from L. mucilago a musty juice, fr. mucus mucus, slime. See Mucus.] 1. (Bot. Chem.) A gummy or gelatinous substance produced in certain plants by the action of water on the cell wall, as in the seeds of quinces, of flax, etc.

2. An aqueous solution of gum, or of substances allied to it; as, medicinal mucilage; mucilage for fastening envelopes.