Lingula

n. pl. -læ (lĭņ"g&uuptack_;*lē).
  1. (Anat.) A tonguelike process or part.
  2. (Zoöl.) Any one of numerous species of brachiopod shells belonging to the genus Lingula, and related genera. See Brachiopoda, and Illustration in Appendix.
    3. Lingula flags (Geol.),
    a group of strata in the lower Silurian or Cambrian system of Wales, in which some of the layers contain vast numbers of a species of Lingula.