A more thorough explanation:

Definition: In law, "mandatory" means something that is required or obligatory.

For example:

• Mandatory authority: This refers to a source of law that a court is required to follow. For instance, a court must follow a statute or a higher court's decision that is mandatory authority.
• Mandatory injunction: This is an order that requires someone to perform a specific act or course of conduct. For example, a court may issue a mandatory injunction to stop someone from building a structure that violates zoning laws.
• Mandatory joinder: This requires the inclusion of a party in a lawsuit. For instance, if a lawsuit involves a contract between two parties, a mandatory joinder may require the inclusion of a third party who has an interest in the contract.
• Mandatory power of appointment: This is the required exercise of the power of disposition given to a person over property that is not their own. For example, if a trust gives a trustee the power to distribute assets to beneficiaries, the trustee may have a mandatory power of appointment that requires them to distribute the assets in a certain way.

These examples illustrate how "mandatory" is used in law to indicate something that is required or obligatory. It is important to follow mandatory requirements to avoid legal consequences.