channel catfishn. An edible freshwater catfish (Ictalurus punctatus) of North America, having spots on the side and long barbels. Also called channel cat.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.chan?nel cat?fish n. a freshwater food fish of the central U.S., Ictalurus punctatus.Also called chan?nel cat`. [1830?40, Amer.] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.