mid-15c., "fortified place, stronghold," from Old French fort "fort, fortress; strong man," noun use of adjective meaning "strong, stout, sturdy; hard, severe, difficult; hard to understand; dreadful, terrible; fortified" (10c.), from Latin fortis "strong, mighty; firm, steadfast; brave, spirited," from Old Latin forctus, which is of unknown etymology. Possibly from PIE root *bhergh- (2) "high, elevated," with derivatives referring to hills and hill-forts, or possibly from *dher- "to hold firmly, support." Figurative use of hold the fort attested from 1590s.

military installation in South Carolina, U.S., begun in 1827, named for U.S. Revolutionary War officer and Congressman Thomas Sumter (1734-1832), "The Carolina Gamecock." The family name is attested from 1206, from Old French sommetier "driver of a pack horse" (see sumpter). The U.S. Civil War is held to have begun with the firing of rebel batteries on the government-held fort on April 12, 1861.

1640s, fort, from French fort "strong point (of a sword blade)," earlier "fort, fortress" (see fort). Meaning "strong point of a person, that in which one excels," is from 1680s. Final -e- added 18c. in imitation of Italian forte "strong."

Estonian capital, from Old Estonian (Finnic) tan-linn "Danish fort," from tan "Danish" + linn "fort, castle." Founded 1219 by Danish king Valdemar II.

county in northern Ireland, from Irish Dun na nGall "fort of the foreigners" (in this case, the Danes); also see Galloway.

older than King Edwin of Northumbria (who often is credited as the source of the name); originally Din Eidyn, Celtic, perhaps literally "fort on a slope." Later the first element was trimmed off and Old English burh "fort" added in its place." Dunedin in New Zealand represents an attempt at the original form.

1724, from Italian fortissimo, superlative of forte "loud, strong," from Latin fortis "strong" (see fort).

city in France in the former province of Lyonnais at the confluence of the Rhone and the Saône, from Gallo-Latin Lugudunum, which is perhaps literally "fort of Lugus," the Celtic god-name, with second element from Celtic *dunon "hill, hill-fort." The fem. adjectival form Lyonnaise is used in cookery in reference to types of onion sauce (1846). During the Revolution the place was renamed Ville-Affranchie "enfranchised town."

music instruction, "loud, loudly," from Italian forte, literally "strong," from Latin fortis "strong" (see fort). Opposed to piano.

1520s, "mystical interpretation of the Old Testament," later "an intriguing society, a small group meeting privately" (1660s), from French cabal, which had both senses, from Medieval Latin cabbala (see cabbala). Popularized in English 1673 as an acronym for five intriguing ministers of Charles II (Clifford, Arlington, Buckingham, Ashley, and Lauderdale), which gave the word its sinister connotations.