What does «excepción» mean in Spanish?

Derogation to normal.

Examples of use in Spanish: "hacer una excepción".
What deviates from the general rule.

Examples of use in Spanish: "no hay regla sin excepción".
Reason alleged by the defendant to render the plaintiff's action ineffective.

Examples of use in Spanish: "excepción dilatoria"; "excepción perentoria".
(a excepción de, o con excepción de) Exception.