1. A sheath; a theca; as, the vagina of the portal vein.
  2. Specifically, the canal which leads from the uterus to the external orifice if the genital canal, or to the cloaca.
  3. The terminal part of the oviduct in insects and various other invertebrates. See Illust., of Spermatheca.
  4. The basal expansion of certain leaves, which inwraps the stem; a sheath.
  5. The shaft of a terminus, from which the bust of figure seems to issue or arise.