1. One
who rules; one
who exercises sway or authority; a governor. "And he made
him ruler over all the land." (Gen. Xii. 43) "A prince and
ruler of the land." (Shak)
2. A straight or curved strip of tree, metal, etc, with a
smooth edge, used for guiding a
pen or
pencil in drawing lines. Cf. Rule, 7 . Parallel ruler. See Parallel.
Source: Websters Vocabulary