Rul"er (?), n.
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 wood, metal, etc., with a smooth edge, used for guiding a pen or pencil in drawing lines. Cf. Rule, n., 7 (a)<-- usu. marked with graduations so that it can be used to measure distances -->.
Parallel ruler. See under Parallel.
© Webster 1913.