pelta

noun4

1. •
   (historical) A small shield, especially one of an approximately elliptical form, or crescent-shaped.

   • Xenophon also mentions bronze peltae, but probably (like hoplite shields) they were only faced with a thin covering of bronze. — 1970
2. •
   (historical) A crescent-shaped design used in mosaics.
3. •
   A crescent-shaped sheet of microtubules that encircles the base of the flagella of a protozoan.

   • The anterior semi-circular pelta surrounds the basal body area and the axostyle forms the longitudinal axis of the cell. — 2012
4. •
   A flat apothecium with no rim.