tour de force n.

c. 1300, "a turn, a shift on duty," from Old French tor, tourn, tourn "a turn, trick, round, circuit, circumference," from torner, tourner "to turn" (see turn (v.)). Sense of "a continued ramble or excursion" is from 1640s. Tour de France as a bicycle race is recorded in English from 1916 (Tour de France Cycliste), distinguished from a motorcar race of the same name. The Grand Tour, a journey through France, Germany, Switzerland, and Italy formerly was the finishing touch in the education of a gentleman.

c. 1300, "physical strength," from Old French force "force, strength; courage, fortitude; violence, power, compulsion" (12c.), from Vulgar Latin *fortia (source also of Old Spanish forzo, Spanish fuerza, Italian forza), noun use of neuter plural of Latin fortis "strong, mighty; firm, steadfast; brave, bold" (see fort).

Meanings "power to convince the mind" and "power exerted against will or consent" are from mid-14c. Meaning "body of armed men, a military organization" first recorded late 14c. (also in Old French). Physics sense is from 1660s; force field attested by 1920. Related: Forces.