Lewis & Short

† chĕlōnĭum, ii, n., = χελώνιον (lit.

  1. I. a tortoise-shell; hence); in mechanics, the similarly formed shield, cramp, or stay in which the axis of the crane or windlass moved, Vitr. 10, 2; 10, 4; 10, 8; 10, 15; 10, 18; 10, 21.
  2. II. A plant, also called cyclaminos, App. Herb. 17.