NM or N.M.abbr. New Mexiconmabbr.1. nanometer2. nautical mile3. nuclear magnetonnMabbr. nanomoleAmerican 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.nm abbreviation for 1. (Units) nautical mile 2. (Units) nanometre NM or N. Mex.abbreviation for (Placename) New MexicoCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014NM or N.M., New Mexico. nm 1. nanometer. 2. nautical mile. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.