plasmo- or plasm-pref. Plasma: plasmin.[From plasma.]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.plasmo- or before a vowel plasm-combining formof, relating to, or resembling plasma: plasmolysis. [from Greek plasma; see plasma]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014plasmo- a combining form representing plasma or cytoplasm: plasmolysis. Also, esp. before a vowel,plasm-. [comb. form, representing Greek plásma. See plasma, -o-] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.