regimen (n.)youdaoicibaDictYouDict[regimen 词源字典]
c. 1400, medical, "course of diet, exercise, etc. for sake of health;" mid-15c., "act of governing," from Old French regimen (14c.), from Latin regimen "rule, guidance, government, means of guidance, rudder," from regere "to rule" (see regal).[regimen etymology, regimen origin, 英语词源]
regiment (n.)youdaoicibaDictYouDict
late 14c., "government, rule, control," from Old French regiment "government, rule" (14c.), from Late Latin regimentum "rule, direction," from Latin regere "to rule" (see regal). Meaning "unit of an army" first recorded 1570s (originally the reference was to permanent organization and discipline), from French. The exact number in the unit varies over time and place.
regiment (v.)youdaoicibaDictYouDict
"to form into a regiment," 1610s, from regiment (n.). General sense of "organize systematically" is from 1690s. Related: Regimented; regimenting.
regimental (adj.)youdaoicibaDictYouDict
1650s, from regiment (n.) + -al (1). As a noun, regimentals, "dress proper to a particular regiment, military uniform," is from 1742.
regimentation (n.)youdaoicibaDictYouDict
1856, noun of action from regiment (v.).
ReginayoudaoicibaDictYouDict
fem. proper name, from Latin, literally "queen;" related to rex (genitive regis) "king" (see regal). Cognate with Sanskrit rajni "queen," Welsh rhyain "maiden, virgin." The city in Canada was named 1882 by the then-governor general of Canada, Marquess of Lorne, in honor of Queen Victoria.
ReginaldyoudaoicibaDictYouDict
masc. proper name, from Old High German Reginald, literally "ruling with power" (see Reynard).
region (n.)youdaoicibaDictYouDict
c. 1300, "tract of land of a considerable but indefinite extent," from Anglo-French regioun, Old French region "land, region, province" (12c.), from Latin regionem (nominative regio) "a district, portion of a country, territory, district; a direction, line; boundary line, limit," noun of state from past participle stem of regere "to direct, rule" (see regal). Phrase in the region of "about" (of numbers, etc.) is recorded from 1961.
regional (adj.)youdaoicibaDictYouDict
early 15c., from Late Latin regionalis "of or belonging to a region or province," from stem of regio (see region). Related: Regionally.
regionalism (n.)youdaoicibaDictYouDict
1878, originally of Italy, "tendency toward regional loyalties" (opposed to nationalism), from regional + -ism. As "a word or phrase of local use" is from 1953.
register (n.1)youdaoicibaDictYouDict
late 14c., from Old French registre (13c.) and directly from Medieval Latin registrum, alteration of Late Latin regesta "list, matters recorded," noun use of Latin regesta, neuter plural of regestus, past participle of regerere "to record; retort," literally "to carry back, bring back" from re- "back" (see re-) + gerere "carry, bear" (see gest).

Also borrowed in Dutch, German, Swedish, Danish. Some senses influenced by association with Latin regere "to rule." Meaning in printing, "exact alignment of presswork" is from 1680s. Musical sense is from 1811, "compass or range of a voice or instrument," hence "series of tones of the same quality" (produced by a voice or instrument). Sense "device by which data is automatically recorded" is 1830, from the verb; hence Cash register (1875).
register (v.)youdaoicibaDictYouDict
late 14c. (transitive), "enter in a listing," from Old French registrer "note down, include" (13c.) and directly from Medieval Latin registrare, from registrum (see register (n.)). Intransitive sense, of instruments, from 1797; of persons and feelings, "make an impression," from 1901. Meaning "to enter one's name in a list" for some purpose is from 1940. Related: Registered; registering. Registered nurse attested from 1879.
register (n.2)youdaoicibaDictYouDict
"assistant court officer in administrative or routine function," 1530s, now chiefly U.S., alteration of registrar (q.v) due to influence of register.
registrant (n.)youdaoicibaDictYouDict
1879; see register + -ant.
registrar (n.)youdaoicibaDictYouDict
1670s, shortening of registrary (1540s), from Medieval Latin registrarius "one who keeps a record" (related to register (n.)). Earlier were registerer (mid-15c.), registrer (late 14c.).
registration (n.)youdaoicibaDictYouDict
1560s, from Middle French registration and directly from Medieval Latin registrationem (nominative registratio) "a registering," noun of action from past participle stem of registrare (see register (v.)).
registry (n.)youdaoicibaDictYouDict
late 15c., "act of registering;" see register + -y (4). Meaning "book of record" is from 1620s.
regnant (adj.)youdaoicibaDictYouDict
"reigning, exercising authority," c. 1600, from Latin regnantem (nominative regnans) "reigning," present participle stem of regnare "to reign" (see reign). Adjective regnal (1610s) means "pertaining to a reign," especially in reference to the day or year a reign began.
regolith (n.)youdaoicibaDictYouDict
1897, from Greek rhegos "rug, blanket," from PIE *reg- (3) "to dye" (see raga) + lithos "stone" (see litho-).
regress (n.)youdaoicibaDictYouDict
late 14c., "act of going back," from Latin regressus "a return, retreat, a going back," noun use of past participle of regredi "to go back," from re- "back" (see re-) + gradi "to step, walk" (see grade (n.)).