Armilla

noun

1. In botany, the frill originally covering the hymenium of agarics and adhering to the stipe after the expansion of the pileus.
2. In archœol., a bracelet or armlet: as, a Roman or Frankish armilla. Also called armil.
3. In machinery, an iron ring, hoop, or brace, in which the gudgeons of a wheel move.
4. In anatomy, the annular ligament of the wrist which binds together the tendons of the hand.
5. Same as armil, 1.