Source : Webster's Revised Unabridged Dictionary (1913)

Membranous \Mem"bra*nous\, a. [Cf. F. membraneux.]
   1. Pertaining to, consisting of, or resembling, membrane; as,
      a membranous covering or lining.

   2. (Bot.) Membranaceous.

   {Membranous croup} (Med.), true croup. See {Croup}.