max·im (m?k?s?m)n. A succinct formulation of a fundamental principle, general truth, or rule of conduct. See Synonyms at saying.[Middle English maxime, from Old French, from Medieval Latin maxima, from maxima (pr?positi?), greatest (premise), feminine of Latin maximus, greatest; see meg- in Indo-European roots.]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.maxim (?mæks?m) n (Literary & Literary Critical Terms) a brief expression of a general truth, principle, or rule of conduct[C15: via French from Medieval Latin, from maxima, in the phrase maxima pr?positio basic axiom (literally: greatest proposition); see maximum]Maxim (?mæks?m) n (Biography) Sir Hiram Stevens. 1840?1916, British inventor of the first automatic machine gun (1884), born in the USCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014max?im (?mæk s?m) n. 1. an expression of a general truth or principle, esp. an aphoristic or sententious one. 2. a principle or rule of conduct. [1400?50; « Medieval Latin maxima