A more thorough explanation:

Definition: Notice is a legal requirement that ensures all parties involved in a case are informed that a lawsuit is pending and that it could affect their interests. The Due Process clauses of the United States Constitution prohibit courts from hearing a case that could adversely affect a party's interest unless that party has been given proper notice. The degree of required notice varies depending on what type of jurisdiction a court intends to exercise.

Example 1: In a case where a court intends to exercise in personam jurisdiction, in-hand service of process is usually required. This means that the party being sued must be personally served with a copy of the lawsuit. For example, if someone is suing their neighbor for property damage, they must personally serve their neighbor with a copy of the lawsuit.

Example 2: In a case where a court intends to exercise in rem jurisdiction, the plaintiff usually must inform all known parties of interest by a reasonably reliable means, and may then inform the rest of the world by "notice by publication" - purchasing a notice in a local newspaper multiple times over a period of several weeks. For example, if the government seizes and sells property for unpaid property taxes, they must inform all known parties with an interest in the property, such as the owner and any lienholders, by a reliable means such as certified mail. They may then inform the rest of the world by publishing a notice in a local newspaper.

Example 3: In Jones v. Flowers, a state seized and sold property for unpaid property taxes. A certified letter meant to notify the owner of the impending sale was returned to the state as "unclaimed." Afterwards, the state made no additional attempt to contact the owner directly. The Court rejected the state's notice as insufficient, emphasizing that notice “must be such as one desirous of actually informing the absentee might reasonably adopt to accomplish it." This example illustrates that notice is not a mere formality and must be sufficient to actually inform the parties involved.

Overall, notice is an important legal requirement that ensures all parties involved in a case are informed and have the opportunity to defend their interests.