*teutā-, Proto-Indo-European root meaning "tribe." It forms all or part of: Deutsch; Dutch; Plattdeutsch; Teuton; Teutonic.
It is the hypothetical source of/evidence for its existence is provided by: Old Irish tuoth "people," Old Lithuanian tauta "people," Old Prussian tauto "country," Oscan touto "community," German Deutsch, Gothic þiuda, Old English þeod "people, race, nation," Old English þeodisc "belonging to the people." But Boutkan says it is probably a substratum word.