re·gent 
(rējənt)
(rējənt)n.
1. One who rules during the minority, absence, or disability of a monarch.
2. One acting as a ruler or governor.
3. A member of a board that governs an institution, such as a state university.
[Middle English, from Old French, from Latin regēns, regent-, ruler, from present participle of regere, to rule; see reg- in the Appendix of Indo-European roots.]
regent·al (-jən-tl) adj.