From Proto-Italic *gʷraus, from Proto-Indo-European *gʷréh₂us, an u-stem adjective regularly enlarged into the i-stem, compare brevis, dulcis, mollis, tenuis, etc. Cognate with Ancient Greek βαρύς (barús), Gothic 𐌺𐌰𐌿𐍂𐌿𐍃 (kaurus, “heavy”), Persian گران (gerân) and Sanskrit गुरु (gurú). See also Latin brūtus.