According to Derksen, ultimately from Proto-Indo-European *dʰr̥Hbʰ-, a zero-grade of *(s)dʰerHbʰ- (“to exert force”). Cognate with dir̂bt (“to walk fast”), Lithuanian di̇̀rbti (“to work”), Proto-Germanic *derbaną (“to work”). An older theory by Karulis derives the term from Proto-Baltic *darbas, from Proto-Indo-European *der-, *dar- (“to tear, to split”). In this analysis, the original meaning was, according to some researchers, “till, plow” (compare Russian дерба́ (derbá, “breaking; newly ploughed field”); the object of this work is Old Norse torf, torfa (“turf, sod, peat”), German Torf (“peat”), English turf, which has the same origin as Russian дёрн (djorn, “sod, turf”)) or, according to others, “wicker-work, wattling, weaving” (compare Belarusian до́раб (dórab, “basket”) (< Proto-Slavic *dorbь), даро́віць (daróvicʹ, “to bend”)). Cognates include Lithuanian dárbas.