noun
today and tomorrow
Refers to the two specific days: today and the following day. Often used when discussing immediate plans or deadlines.
今日明日のうちに返事をください。
Please give me an answer within today or tomorrow.
noun
today or tomorrow; in a day or two; very soon
Used to express that something will happen imminently, within the next couple of days. The exact day is not specified, but the timeframe is very short.
今日明日にも雨が降り出すかもしれない。
It might start raining any day now.
彼は今日明日にでも引っ越すらしい。
It seems he's moving out very soon, maybe today or tomorrow.
今明日 is a more formal or literary synonym for 'today and tomorrow', while 今日明日 is the common everyday term.
Compound of 今日 (きょう, 'today') and 明日 (あす, 'tomorrow'). The reading あす is a slightly older or more formal variant of あした, but is preserved in this fixed expression.