DAY — one of the most elastic words in the Hebrew Bible, and the reason the length of the creation 'days' has been debated for two thousand years. It means the daylight hours (Genesis 1:5, 'God named the light DAY'), a 24-hour calendar day, AND an indefinite stretch of time — an age: 'in the DAY that Jehovah made earth and heaven' (2:4) folds the whole creation week into a single yom, and 'the DAY of Jehovah' names a whole era of judgment. So the six 'days' of Genesis 1 can be read as ordinary days OR as long ages (the 'day-age' reading — ancient, going back to Augustine, and the way many hold the text and the ~13.8-billion-year cosmos together). This translation renders it plainly 'day' and lays out the readings without voting — see the note at 1:5, or the fuller discussion on the Dear Mr. Librarian page. → first discussed at Gen 1:5