- a state in the NE central United States: a part of the Midwest. 41,222 sq. mi. (106,765 sq. km). Capital: Columbus. Abbreviation: OH (for use with zip code), O.
- a river formed by the confluence of the Allegheny and Monongahela rivers, flowing SW from Pittsburgh, Pa., to the Mississippi in S Illinois. 981 miles (1580 km) long.
- a state of the central US, in the Midwest on Lake Erie: consists of prairies in the W and the Allegheny plateau in the E, the Ohio River forming the S and most of the E borders. Capital: Columbus. Pop: 11 435 798 (2003 est). Area: 107 044 sq km (41 330 sq miles)Abbreviation and zip code: OH
- a river in the eastern US, formed by the confluence of the Allegheny and Monongahela Rivers at Pittsburgh: flows generally W and SW to join the Mississippi at Cairo, Illinois, as its chief E tributary. Length: 1570 km (975 miles)
originally used of the river, from Seneca (Iroquoian) ohi:yo’, proper name from ohi:yo:h, literally “good river.” The Seneca also used this of the Allegheny, which they considered the headwaters of the Ohio. Related: Ohian (1819); Ohioan (1818). State in the northern United States bordered by Michigan and Lake Erie to the north, Pennsylvania and West Virginia to the east, West Virginia and Kentucky to the south, and Indiana to the west. Its capital is Columbus, and its largest city is Cleveland.