ey

Inherited from Middle English ei, ey, from Old English ǣġ, from Proto-West Germanic *aij, from Proto-Germanic *ajją (“egg”), from Proto-Indo-European *h₂ōwyóm (“egg”), probably from *h₂éwis (“bird”), from *h₂ew- (“to consume”). Doublet of egg, huevo, oeuf, and ovum. Cognates Cognate with North Frisian ai (“egg”), Saterland Frisian Oai (“egg”), West Frisian aai, aei (“egg”), Bavarian Oa (“egg”), Dutch ei (“egg”), German Ei (“egg”), German Low German Ai, Ägg (“egg”), Limburgish ei, Éï (“egg”), Luxembourgish Ee (“egg”), Mòcheno oi (“egg”), Vilamovian e (“egg”), Yiddish איי (ey, “egg”), Danish æg (“egg”), Faroese, Icelandic, Norwegian Bokmål, and Norwegian Nynorsk egg (“egg”), Swedish ägg (“egg”), Crimean Gothic ada (“egg”); also Breton vi (“egg”), Cornish oy (“egg”), Welsh wy (“egg”), Latin ōvum (“egg”), Greek αβγό (avgó), αυγό (avgó, “egg”), Albanian vo (“egg”), Belarusian and Russian яйцо́ (jajcó, “egg”), Bulgarian яйце́ (jajcé, “egg”), Czech vejce (“egg”), Macedonian јајце (jajce, “egg”), Polish jajo (“egg”), Serbo-Croatian ја́јце, jájce (“egg”), Slovak vajce (“egg”), Slovene jájce (“egg”), Ukrainian яйце́ (jajcé, “egg”), Ossetian айк (ajk), айкӕ (ajkæ, “egg”), Armenian ձու (ju, “egg”), Northern Kurdish hêk (“egg”), Southern Kurdish خا (xa, “egg”), Zazaki hak (“egg”), Pashto هګۍ (hagë́y), ويه (wë́ya, “egg”), Persian خاگ (xâg), خایه (xâye, “egg”). This native English form was displaced by the Old Norse–derived egg in the 16th century.

来源：wiktionary