Raffinate

Part of speech: noun, verb

Definitions

1. The product that remains after beneficial elements are removed from a mixture
2. The substance left behind following the extraction of useful components from raw materials
3. The residue obtained after the process of removing desirable elements from a mixture serves as the less valuable byproduct

Etymology: The verb "raffinate" is a bit of a puzzle, but the noun is the older and more settled sense. It comes from French "raffiner", meaning to refine or purify, which itself is built on "affiner", to make fine. The French prefix "ra-" (from Latin "re-") carries a sense of repetition or intensity, so the root idea is making something finer again and again. That is an odd fit for what the word now names: the leftover liquid after the valuable part has been drawn off. The chemistry explains the reversal. In liquid-liquid extraction, a solvent pulls a target substance out of a mixture, and the material that remains, now depleted of that substance, is called the raffinate, while the solvent carrying the extracted part is the extract. The name stuck to the discarded side because the process was built around refining the product, and the leftover is what the refining produces.