1620s, "poet or bard," specifically "Celtic divinely inspired poet" (1728), from Latin vates "sooth-sayer, prophet, seer," from a Celtic source akin to Old Irish faith "poet," Welsh gwawd "poem," from PIE root *wet- (1) "to blow; inspire, spiritually arouse" (cognates: Old English wod "mad, frenzied," god-name Woden; see wood (adj.)). Hence vaticination "oracular prediction" (c. 1600).