Geneva, Lake also Lake Le·man (l??m?n, l?-m?N?) A lake on the Swiss-French border between the Alps and the Jura Mountains. It is traversed east to west by the Rhone River.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.