early 13c., "illustrious, distinguished, worthy of honor or respect," from O.Fr. noble, from L. nobilis "well-known, famous, renowned, of superior birth," earlier gnobilis, lit. "knowable," from gnoscere "to come to know," from PIE base *gno- (see know
). The prominent Roman
families, which were "well known," provided most of the Republic's public officials. Meaning "distinguished by rank, title, or birth" is first recorded late 13c. Sense of "having lofty character, having high moral qualities" is from c.1600. The noble gases (1902) so called for their inactivity or interness; a use of the word that had been applied in M.E. to precious stones, metals, etc., of similar quality (late 14c.), from the sense of "having admirable properties" (c.1300).