A more thorough explanation:

Definition: A rider is an additional document that modifies or supplements the primary document. It can add new terms to a contract or amend existing ones. In legislative contexts, a rider is an amendment to a bill that is not directly related to the bill's main purpose.

Example: In Blackburn Food Corp. v. Ardi, Inc., a lease contained a rider that gave tenants the option to purchase the premises. This rider added a new term to the lease agreement that was not originally included.

Example: In a legislative context, a bill that funds a program may have a rider attached to it that changes the permanent law governing that program. For example, a bill that funds a healthcare program may have a rider attached to it that changes the eligibility requirements for that program.

Explanation: Both examples illustrate how a rider can modify or supplement a primary document. In the first example, the rider added a new term to the lease agreement that gave tenants the option to purchase the premises. In the second example, the rider changed the permanent law governing a program that was funded by a bill. Both examples show how a rider can be used to make changes to a document or law that are not directly related to the main purpose of that document or law.