"state in which supreme or executive power rests in the people via representatives chosen by citizens entitled to vote," c. 1600, from French république (15c.), from Latin respublica (ablative republica) "the common weal, a commonwealth, state, republic," literally res publica "public interest, the state," from res "affair, matter, thing" (see re) + publica, fem. of publicus "public" (see public (adj.)).
Applied to particular states so constituted by 1630s. The notion of "community in which there is a certain equality of members" is behind such expressions as republic of letters "collective body of those engaged in literary pursuits," attested from 1702.
1712, "belonging to a republic, of the nature of a republic, consonant to the principles of a republic," from republic + -an. With capital R-, "of, pertaining to, or favoring one of the various American parties that have been called Republican," by 1806 (the modern GOP dates from 1854). The French republican calendar was in use from Nov. 26, 1793 to Dec. 31, 1805. Earlier adjectives included republical (1650s), republicarian (1680s).
"national language of the Republic of the Philippines," 1936, from Tagalog form of obsolete Spanish Pilipino (see Filipino).