O·kla·ho·ma (??kl?-h??m?) Abbr. OK or Okla. A state of the south-central United States. It was admitted as the 46th state in 1907. The western part was organized in 1890 as the Oklahoma Territory, which was merged with the adjoining Indian Territory to form the present state boundaries. The Dust Bowl of the 1930s forced many farmers to move west as migrant laborers. Oklahoma City is the capital and the largest city.O?kla·ho?man adj. & n.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.Oklahoma (???kl??h??m?) n (Placename) a state in the S central US: consists of plains in the west, rising to mountains in the southwest and east; important for oil. Capital: Oklahoma City. Pop: 3 511 532 (2003 est). Area: 181 185 sq km (69 956 sq miles). Abbreviation: Okla. or OK (with zip code)Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014O?kla?ho?ma (?o? kl??ho? m?) n. a state in the S central United States. 3,450,654; 69,919 sq. mi. (181,090 sq. km). Cap.: Oklahoma City. Abbr.: OK, Okla. O`kla?ho?man, adj., n. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.