single-barreled water-cooled machine gun, 1885 (Maxim gun), named for inventor, U.S.-born British engineer Sir Hiram S. Maxim (1840-1916).
early 15c., maxime, "an axiom, statement of a self-evident truth," from Old French maxime, from Late Latin maxima, shortened from phrases such as maxima propositio (Boethius), maxima sententarium "axiom," literally "greatest or chief premise, greatest among propositions" (one which is general and absolute), from fem. of maximus "greatest," from PIE *mag-samo-, superlative form of root *meg- "great."
The modern meaning "summary statement of an established or accepted proposition serving as a rule or guide, a proposition ostensibly expressing some general truth" is from 1590s.
"short, pithy statement of general truth," 1570s, from Greek gnōmē "judgment, opinion; maxim, the opinion of wise men," from PIE root *gno- "to know."
also dict, "a saying, maxim, statement," late 14c., from Latin dictum "a thing said" (see dictum). A word long obsolete, but it figures in what is probably the first book printed in English, Caxton's issue of Anthony Woodville's "Dictes and Sayings of the Philosophers."
1590s, "positive order or command;" 1610s "authoritative rule, maxim, or precept," from Latin dictatum "a thing said, something dictated," noun use of neuter past participle of dictare "say often, prescribe," frequentative of dicere "to say, speak" (from PIE root *deik- "to show," also "pronounce solemnly").
[proverb, saying, maxim], Middle English saue, at first in a general sense, "what is said, talk, words," from Old English sagu "saying, discourse, speech, study, tradition, tale," from Proto-Germanic *saga-, *sagon- (source also of Middle Low German, Middle Dutch sage, zage, German Sage "legend, fable, saga, myth, tradition," Old Norse saga "story, tale, saga"), from PIE root *sek(w)- "to say, utter" (see say (v.)).
The surviving specific sense of "proverb, saying, maxim" is by late 13c. "[A] contemptuous term for an expression that is more common than wise" [Century Dictionary].