From Middle English leche (“physician”), from Old English lǣċe (“doctor, physician”), from Proto-West Germanic *lākī, from Proto-Germanic *lēkijaz (“doctor”), of disputed origin, but usually thought to be connected with Proto-Celtic (compare Old Irish líaig (“doctor, physician”)); perhaps ultimately from Proto-Indo-European *leǵ- (“to collect, gather”).
Cognate with Old Frisian lētza (“physician”), Old Saxon lāki (“physician”), Old High German lāhhi (“doctor, healer”), Danish læge (“doctor, surgeon”), Gothic 𐌻𐌴𐌺𐌴𐌹𐍃 (lēkeis, “physician”). Slavic words such as Serbo-Croatian ljèkār, Polish lekarz (“physician, doctor”) are usually considered to be borrowings from Germanic.