1. An innominate contract in which a person agrees to do something for another person who agrees to do something in return, such as an agreement to marry.
2. The consideration in such a contract. See innominate contract under CONTRACT.
“These valuable considerations are divided by the civilians into four species…. The second species is, facio, ut facias: as when I agree with a man to do his work for him, if he will do mine for me; or if two persons agree to marry together; or to do any positive acts on both sides. Or, it may be to forbear on one side in consideration of something done on the other; as, that in consideration A, the tenant, will repair his house, B, the landlord, will not sue him for waste.” 2 William Blackstone, Commentaries on the Laws of England 444 (1766).