Definition of the word residuum

The word "residuum" originated from the Latin word "residuus," which means "that which remains," "left over," or "remnant." In medieval Latin, it was commonly used to refer to the leftover portion of a substance after distillation or filtration. This scientific meaning of "residuum" was adopted in the 17th century and used primarily in the fields of chemistry and medicine to describe the remaining matter or solid substance after solvents or other agents have been removed. For instance, in the process of purifying a substance, the residuum is the undesirable impurities or byproducts that remain after extraction or isolation. The term "residuum" is also applied in certain social sciences to describe a group of people who are left out or excluded from society due to factors such as poverty, disability, or ethnicity. This usage of "residuum" has migrated from medicine, where it was used to describe a group of individuals left behind by societal advancements, such as those affected by diseases with no known cure. In both scientific and social contexts, the word "residuum" suggests a remainder or leftover quantity that is difficult to eliminate or remove entirely.