Addendum Definition

An addition to a contract or completed written document, such as a detailed explanation of a contract clause or a proposed change to a contract. House purchase agreements often included addenda (plural of addendum), covering subjects such as payment schedules and other financing terms, what appliances are included in the sale, and date of transfer of title. An addendum should be signed separately and attached to the original agreement so that there will be no confusion as to what is included or intended.