The phrase "each night" refers to an event or action that occurs every night. It can be used interchangeably with other phrases or synonyms such as "nightly," "every evening," "night after night," "every night without fail," or "on a nightly basis." Each of these synonyms carries the same meaning as "each night" and can be used according to one's preference and style of writing. These terms can be used in different contexts such as describing a daily routine or a habitual activity that takes place during the night, highlighting the repetitive nature of the activity.