Abolish vs Annul - What's the difference?

Annul is a synonym of abolish.

is that abolish is to end a law, system, institution, custom or practice while annul is to formally revoke the validity of.

(es)

To end a law, system, institution, custom or practice.

Slavery was abolished in the nineteenth century.

* 2002', William Schabas, ''The '''abolition of the death penalty in international law (Cambridge University Press):

(archaic) To put an end to or destroy, as a physical object; to wipe out.

* :

And with thy blood abolish so reproachful blot.

* :

His quick instinctive hand Caught at the hilt, as to abolish him.

* abrogate, annul, cancel, dissolve, nullify, repeal, revoke

* establish, found

To formally revoke the validity of.

To dissolve (a marital union) on the grounds that it is not valid.

* annulment