Affirmative Defense: A defense raised by a defendant that admits the plaintiff's claim but offers additional facts that legally excuse or justify the defendant's actions.
Compulsory Counterclaim: A counterclaim that a defendant is required to bring in the same lawsuit, as it arises out of the same transaction or occurrence as the plaintiff's claim.
Permissive Counterclaim: A counterclaim that a defendant may choose to bring, but is not required to, as it does not arise out of the same transaction or occurrence as the plaintiff's claim.