noun, adverb
every day and every night; day after day; daily
Emphasizes continuous repetition both day and night; often used in poetic or emphatic contexts.
日ごと夜ごと練習を重ねた。
I practiced day after day and night after night.
日ごと夜ごと彼女のことを考えている。
I think of her every day and every night.
Compound of 日 (ひ, 'day') + ごと ('every') + 夜 (よ, 'night') + ごと ('every'). The suffix ごと attaches to nouns to mean 'each' or 'every'.