The difference between Relic and Residue

Relic as a noun:

That which remains; that which is left after loss or decay; a remaining portion.

Relic as a noun:

Something old and outdated, possibly kept for sentimental reasons.

Relic as a noun (religion):

A part of the body of a saint, or an ancient religious object, kept for veneration.

Relic as a verb (transitive, uncommon, often of guitars):

To cause (an object) to appear old or worn, to distress.

Residue as a noun:

Whatever remains after something else has been removed.

Residue as a noun (chemistry):

The substance that remains after evaporation, distillation, filtration or any similar process.

Residue as a noun (biochemistry):

A molecule that is released from a polymer after bonds between neighbouring monomers are broken, such as an amino acid in a polypeptide chain.

Residue as a noun (legal):

Whatever property or effects are left in an estate after payment of all debts, other charges and deduction of what is specifically bequeathed by the testator.

Residue as a noun (mathematics):

A form of complex number, proportional to the contour integral of a meromorphic function along a path enclosing one of its singularities.