tūkstantis
From Proto-Balto-Slavic *tuHsontis, from Proto-Indo-European *tuHsont-, *tuHsenti-. Akin to Latvian tūkstotis, Russian ты́сяча (týsjača), Polish tysiąc, English thousand, German tausend, Gothic 𐌸𐌿𐍃𐌿𐌽𐌳𐌹 (þusundi).