DSL (d???s??l?)n. Any of various technologies used to create high-bandwidth network connections over standard telephone lines, often in providing internet service to homes.[d(igital) s(ubscriber) l(ine).]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.DSL abbreviation for (Telecommunications) digital subscriber line Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014DSL Digital Subscriber Line: a technology that allows high-speed transmission of data, audio, and video, usu. over standard telephone lines; a form of broadband transmission. [1995?2000] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.