"Residually" is defined as something that remains or is left over after a process or event. Synonyms for "residually" may include "remnant", "remain", "lingering", "leftover", "trace", "remainder", "leaving", "vestige", "remains", "echo", and "vestigial". These synonyms can be used in various contexts, such as in science, math, and business. In science, residual matter refers to matter remaining after a chemical reaction, while in mathematics, it refers to the reminder after subtracting. In business, residual income refers to income earned after expenses and taxes have been deducted. Overall, synonyms for "residually" provide a way to describe the remnants or remains of something that has occurred.