From Middle English day, from Old English dæġ ("day"), from Proto-West Germanic *dag, from Proto-Germanic *dagaz ("day"), from Proto-Indo-European, from *dʰegʷʰ-.
Cognate with Saterland Frisian Dai ("day"), West Frisian dei ("day"), Dutch dag ("day"), German Low German Dag ("day"), Alemannic German Däi, German Tag ("day"), Swedish, Norwegian and Danish dag ("day"), Icelandic dagur ("day"), Gothic 𐌳𐌰𐌲𐍃 ("dags"). Cognate also with Albanian djeg ("to burn"), Lithuanian degti ("to burn"), Tocharian A tsäk-, Russian жечь ("to burn") from *degti, дёготь, Sanskrit दाह ("heat"), दहति, Latin foveō ("to warm, keep warm, incubate").