D defs.my
Entry 3 senses Webster, 1913

Rod

/räd/ · IPA /ɹɑd/
01 n. A straight and slender stick; a wand; hence, any slender bar, as of wood or metal (applied to various purposes).
  1. 1.
    A straight and slender stick; a wand; hence, any slender bar, as of wood or metal (applied to various purposes).
    “He that spareth his rod hateth his son.” — Prov. xiii. 24.
  2. 2.
    A kind of sceptor, or badge of office; hence, figuratively, power; authority; tyranny; oppression.(Mach. & Structure)
  3. 3.
    A measure of length containing sixteen and a half feet; -- called also perch, and pole. Also: perch, pole
Phrases & compounds
Black rod — See in the Vocabulary.
Rods and cones — the elongated cells or elements of the sensory layer of the retina, some of which are cylindrical, others somewhat conical.