Regulate
late Middle English (in the sense ‘control by rules’): from late Latin regulat- ‘directed, regulated’, from the verb regulare, from Latin regula ‘rule’.
wiktionary
Borrowed from Latin regulatus, past participle of regulō(“to direct, rule, regulate”), from regula(“rule”), from regō(“to keep straight, direct, govern, rule”). Compare regle, rail.
etymonline
regulate (v.)
early 15c., regulaten, "adjust by rule, method, or control," from Late Latin regulatus, past participle of regulare "to control by rule, direct," from Latin regula "rule, straight piece of wood" (from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule").
Meaning "to govern by restriction" is from 1620s. Sense of "adjust (a clock, etc.) with reference to a standard of accuracy" is by 1660s. Related: Regulated; regulating.
