Of the nature of or pertaining to a republic or common wealth: as, a republican constitution or government.Consonant to the principles of a republic: as, republican sentiments or opinions; republican manners.Of or pertaining to or favoring the Republican party: as, a Republican senator. See below.In ornithology, living in community; nesting or breeding in common: as, the republican or sociable grosbeak, Philetærus socius; the republican swallow, formerly called Hirundo respublicana. See cuts under hive-nest.In United States history:n. One who favors or prefers a republican form of government.n. A member of a republican party; specifically , in United States history, a member of the Republican party.n. In ornithology, the republican swallow.