DAY ONE is a phrase that can refer to the first day of something, such as a new job or a new year. The crossword solutions for DAY ONE are OUTSET (6 letters), ONSET (5 letters), and DAWNOFTIME (10 letters). OUTSET refers to the beginning of something, while ONSET is the start of something, usually in reference to an illness or event. DAWNOFTIME is a phrase that refers to the very beginning of something, often used to describe the start of a new era.