nu·cle·ase (no?o?kl?-?s?, -?z?, nyo?o?-)n. Any of several enzymes, including the endonucleases and the exonucleases, that hydrolyze bonds between nucleotides in nucleic acids.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.nuclease (?nju?kl??e?z) n (Biochemistry) any of a group of enzymes that hydrolyse nucleic acids to simple nucleotidesCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014nu?cle?ase (?nu kli?e?s, -?e?z, ?nyu-) n. any enzyme that catalyzes the hydrolysis of nucleic acids. [1900?05] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.