Residue Definition (Chemistry)

What Is a Residue?

A residue can be an undesirable by-product of a chemical reaction.
A residue can be an undesirable by-product of a chemical reaction. C. Allan Morgan / Getty Images

Residue Definition: Residue has several meanings in chemistry.

  1. Residue is the matter left in a container after evaporation or distillation has occurred.
  2. Residue is the undesirable byproduct of a chemical reaction.
  3. Residue is recognizable molecular part of a larger molecule. For example, an amino acid is the residue of a larger protein chain.