A more thorough explanation:

Definition: Available is an adjective that means legally valid. It refers to something that can be used or accessed.

Examples:

• Available claims: Claims that can be legally used in a court of law.
• Available defenses: Defenses that can be legally used in a court of law.
• Available seats: Seats that can be accessed or used.

The examples illustrate that something is available when it is legally valid and can be used or accessed. Available claims and defenses are those that can be used in a court of law. Available seats are those that can be accessed or used by someone.