pre·cau·tion (pr?-kô?sh?n)n.1. An action taken in advance to protect against possible danger, failure, or injury; a safeguard: followed safety precautions when using heavy machinery.2. Caution practiced in advance; forethought or circumspection: a need for precaution when planning a vacation.[Late Latin praecauti?, praecauti?n-, from praecautus, past participle of Latin praecav?re, to guard against : prae-, pre- + cav?re, to beware.]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.precaution (pr??k????n) n1. an action taken to avoid a dangerous or undesirable event2. caution practised beforehand; circumspection[C17: from French, from Late Latin praecauti?, from Latin praecav?re to guard against, from prae before + cav?re to beware] pre?cautionary, pre?cautional adj pre?cautious adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014pre?cau?tion (pr??k? ??n) n. 1. a measure taken in advance to avert possible harm or misfortune. 2. caution employed beforehand; prudent foresight. v.t. 3. to forewarn; put on guard. [1595?1605;