A sharp-crested longitudinal sand dune common to the Sahara and ranging up to 300 m (984 ft) in height and 300 km (186 mi) in length.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.