\Rod\, n. [The same word as rood. See {Rood}.]
1. A straight and slender stick; a wand; hence, any slender
   bar, as of wood or metal (applied to various purposes).
   Specifically:
   (a) An instrument of punishment or correction;
       figuratively, chastisement.
             He that spareth his rod hateth his son. --Prov.
                                               xiii. 24.
   (b) A kind of sceptor, or badge of office; hence,
       figuratively, power; authority; tyranny; oppression.
       ``The rod, and bird of peace.'' --Shak.
   (c) A support for a fishing line; a fish pole. --Gay.
   (d) (Mach. & Structure) A member used in tension, as for
       sustaining a suspended weight, or in tension and
       compression, as for transmitting reciprocating motion,
       etc.; a connecting bar.
   (e) An instrument for measuring.
2. A measure of length containing sixteen and a half feet; --
   called also {perch}, and {pole}.
{Black rod}. See in the Vocabulary.
{Rods and cones} (Anat.), the elongated cells or elements of
   the sensory layer of the retina, some of which are
   cylindrical, others somewhat conical.