something that remains after a part, esp the greater part, has been is taken away, separated, or used up designated; a remnant
the part of a deceased person's estate that remains after the payment of all debts and bequests
a substance remaining after a chemical processing, e.g. distillation, or combustion treatment to extract something useful or valuable
[Middle English via French from Latin residuum, neuter of residuus left over, from residēre: see reside]