Overmorrow, a rarely used word, refers to the day after tomorrow. Although lesser-known, there are a few synonyms that can be used interchangeably to express the same meaning. One substitute is "postmorrow", a term that also means the day following tomorrow. Another option is to use the phrase "the day after next", which provides a clear and simple alternative to overmorrow. Additionally, one could use "two days from now" or "the morrow after next" to convey the concept of overmorrow. While these synonyms might be less common, they offer individuals a variety of options when referring to the day that follows tomorrow.