NdThe symbol for neodymium.NDabbr.1. no date2. or N.D. North DakotaNorth Dakota Abbr. ND or N.D. or N.Dak. A state of the north-central United States bordering on Canada. It was admitted as the 39th state in 1889. Acquired through the Louisiana Purchase (1803) and a border treaty with Great Britain (1818), the region became part of the Dakota Territory in 1861. It was set off from South Dakota when statehood was achieved. Bismarck is the capital and Fargo the largest city.North Dakotan 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.