coel- prefix (Biology) indicating a cavity within a body or a hollow organ or part: coelacanth; coelenterate; coelenteron. [New Latin, from Greek koilos hollow]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014coel- , a combining form meaning ?cavity?: coelenteron. Compare -cele, -coele. [comb. form representing Greek koîlos hollow; akin to cave] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.