The highest-ranking corporate officer or executive officer of a corporation, company, or agency, responsible for carrying out the policies of the board of directors on a day-to-day basis; CEO.
A person who rules or governs; someone or something that exercises dominion or controlling power over others.
A (usually rigid), flat, rectangular measuring or drawing device with graduations in units of measurement; a straightedge with markings.
To beat with a ruler (as a traditional school punishment).