Entry 1 sense Webster, 1913 Whatso · What·so · IPA 01 indef. pron. Whatsoever; whosoever; whatever; anything that. 1. Whatsoever; whosoever; whatever; anything that.[Obs.] “Whatso he were, of high or low estate.” — Chaucer. “Whatso the heaven in his wide vault contains.” — Spenser.