"From day on" can be used in various contexts to signify the beginning of a new phase or era. Some synonyms for this phrase could include "henceforth," "from now on," "starting today," "from this moment forward," "beginning now," or "moving forward." These words can be used interchangeably with "from day on" to convey similar meanings. Whether it's the start of a new personal or professional journey, or a change in attitude or behavior, these phrases all imply a sense of resolution to adopt a new way of thinking or living. Their use can signify a moment of clarity or commitment to improvement and growth.