Oes 'na derm am 'deal memo'?

...yng nghyd-destun grwpiau sydd am berfformio mewn gŵyl gerddorol.

Dyma be ddywed Google:

Deal Memos are the term that independent producers use for employment contracts. Since the word "contract" implies something legally detailed and binding, the term "memo" is used to suggest an agreement somewhat less formal. Do not be mislead; a Deal Memo is a contract and is binding.

Fase Taro Bargen yn addas? neu rhywbeth sy'n cynnwys telerau neu drefniant?

Diolch,
Dafydd