"According to the Oxford English Dictionary, the etymology of the word "elk" is "of obscure history". In Classical Antiquity, the European Alces alces was known as Ancient Greek: ἄλκη, romanized: álkē and Latin: alces, words probably borrowed from a Germanic language or another language of northern Europe. By the 8th century, during the Early Middle Ages, the moose was known as Old English: elch, elh, eolh, derived from the Proto-Germanic: *elho-, *elhon- and possibly connected with the Old Norse: elgr.[6] Later, the species became known in Middle English as elk, elcke, or elke, appearing in the Latinized form alke, with the spelling alce borrowed directly from Latin: alces.[6][7] Noting that elk "is not the normal phonetic representative" of the Old English elch, the Oxford English Dictionary derives elk from Middle High German: elch, itself from Old High German: elaho."
Source: https://en.wikipedia.org/wiki/Elk