An addendum is a thing to be added; an addition. For example, it may be used to add supplemental terms or conditions to a contract or make corrections or supply omissions to a document. An addendum is often used to supply additional terms to standardized contracts, such as leases. Addendum is singular; the plural form is addenda.
Para su conveniencia, debajo del texto en español le brindamos la versión completa de este formulario en inglés. For your convenience, the complete English version of this form is attached below the Spanish version.