1861 as a place name, originally applied by U.S. Congress to a proposed territorial division centered in what is now eastern Colorado; said at the time to mean "Gem of the Mountains" but probably rather from Kiowa-Apache (Athabaskan) idaahe "enemy," a name applied by them to the Comanches. Modern Idaho was organized 1861 as a county in Washington Territory; in 1863 became a territory in its own right and it was admitted as a state in 1890.

native people of Idaho and vicinity, and their language, from French Nez Percé, literally "pierced nose." In reference to an early custom of the people of wearing shell ornaments in pierced septums.

breed of horses favored by Indian tribes in U.S. West, 1849, either from Opelousa (perhaps from Choctaw api losa "black body") in Louisiana, or from the name of the Palouse Indians, who lived near the river of that name in Idaho, whose name is from Sahaptin palou:s "what is standing up in the water."

city in north-central France, Roman Senones, the capital of the Gaulish people of the same name.

capital of Afghanistan, named for its river, which carries a name of unknown origin.

Russian capital, named for the Moskva River, the name of which is of unknown origin. Moscow mule vodka cocktail is attested from 1950.

southern Vietnamese city, capital of former South Vietnam, named for its river, which bears a name of uncertain origin.

so named 1868, from Japanese to "east" + kyo "capital;" its earlier name was Edo, literally "estuary."

from 330 C.E. to 1930 the name of what is now Istanbul and formerly was Byzantium, the city on the European side of the Bosphorus that served as the former capital of the Byzantine and Ottoman empires, from Greek Konstantinou polis "Constantine's city," named for Roman emperor Flavius Valerius Aurelius Constantinus (see Constantine), who transferred the Roman capital there.

Canadian capital, founded 1827 as Bytown, named for English officer John By, who oversaw construction of the canal there; renamed 1854, when it became capital, for the Ottawa River, which took its name from the Algonquian people who lived in Michigan and Ontario. Their name is said to be from adawe "to trade."