NTPabbr. normal temperature and pressureAmerican 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.NTP abbreviation for (General Physics) normal temperature and pressure: standard conditions of 0°C temperature and 101.325 kPa (760 mmHg) pressure. Also: STP Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014