memorandum / memoranda / memorandums
Plural of memorandum: memorandums vs. memoranda, and memoranda used for a single document.
One is a memorandum. More than one are memorandums or memoranda. Memorandums is the ordinary English plural. Memoranda is the Latin plural. Do not use a memoranda.
Examples
Usetwo memorandums
Usetwo memoranda
Avoida memoranda