A(n) ______ is essentially an agreement or promise between parties.

A contract is fundamentally an agreement or promise between parties that creates legal obligations enforceable by law. It serves as the foundational element of many transactions in business and personal dealings, ensuring that all parties understand their rights and responsibilities. In essence, a contract outlines the terms of an arrangement, detailing what is expected from each party involved. This could involve the exchange of goods, services, or any other agreed-upon duties.

The other terms listed—addendum, amendment, and disclosure—have specific meanings that relate to contracts but do not represent a standalone agreement. An addendum is an additional document that modifies or adds to the existing contract, whereas an amendment changes specific terms of a contract while keeping the original document intact. A disclosure refers to providing relevant information, particularly in legal or financial contexts, but it does not constitute an agreement or promise itself. Thus, the term that accurately describes an agreement or promise between parties is a contract.