温泉卵 おんせんたまご Also written 温泉たまご, 温泉玉子 Meanings Noun egg slow-boiled so that the yolk is hard but the white is still soft (traditionally cooked in a hot spring) Kanji 温 warm. Read as オン. 泉 wellspring. Read as セン. 卵 egg. Read as たまご. Example sentences おみやげの温泉卵だよ。It's a souvenir onsen egg. Jinuma: Japanese Dictionary · Word lists