c. 1400, from Latin ergo "therefore, in consequence of," possibly contracted from *e rogo "from the direction of," from ex "out of" (see ex-) + noun from regere "to direct, to guide" (from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule"). Used in logic to introduce the conclusion of a complete and necessary syllogism.

"mob rule, government by the disorderly classes," 1754, a hybrid from mob (n.) + -cracy "rule or government by." Related: Mobocrat "leader of a mob, a demagogue" (1798); mobocratic.

"rule despotically or cruelly; rule tyrannically," late 15c., from French tyranniser (14c.), from tyrannie (see tyranny). Greek tyrannizein meant "to take the part of tyrants" in politics. Related: Tyrannized; tyrannizing.

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.

late 14c., misreulen, "rule badly, govern unwisely or oppressively," also "conduct oneself badly, misbehave;" from mis- (1) "badly, wrongly" + rule (v.). Related: Misruled; misruling.

1650s, "independent power, self-sustained power, self-government" (obsolete), from French autocratie, from Latinized form of Greek autokrateia "absolute rule, rule by oneself," abstract noun from autokratēs "ruling by oneself," from autos "self" (see auto-) + kratia "rule" (see -cracy). The meaning "absolute government, unlimited political power invested in a single person" is recorded from 1855.

1701, "pertaining to a dictator; absolute, unlimited;" see dictator + -ial. Meaning "imperious, overbearing" is from 1704. Related: Dictatorially. Earlier in the sense "pertaining to a dictator" were dictatorian (1640s); dictator-like (1580s). "Dictatorial implies, on the one hand, a disposition to rule, and, on the other, a sharp insistence upon having one's orders accepted or carried out." [Century Dictionary]

"rule by old men," 1830, a Latinized compound of Greek stem of geron (genitive gerontos) "old man" (from PIE root *gere- (1) "to grow old") + kratia "rule" (see -cracy). Related: Gerontocratic.

German masc. name and surname, literally "folk-rule" (Dutch Diederik), from Old High German Theodric, from theuda "folk, people" (see Teutonic) + rihhi "rule," from Proto-Germanic *rikja "rule," from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule." Variants or familiar forms include Derrick, Dierks, Dieter, Dirk. Compare Theodoric. Theodric the Ostrogoth, who held sway in Italy 493-526, appears in later German tales as Dietrich von Bern (Verona).

late 14c., "upright, not bending," from Latin erectus "upright, elevated, lofty; eager, alert, aroused; resolute; arrogant," past participle of erigere "raise or set up," from e- "up, out of" + regere "to direct, keep straight, guide" (from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule").