Latin. I do that you may give, I do that you may do. For an explanation of these phrases, see Do ut des.
A species of contract in the civil law, which occurs when I agree with a man to do his work for him if he will do mine for me; If two persons agree to marry together, or to do any other positive acts on both sides. It may be to forbear on one side in consideration of something done on the other. 2 Bl. Com. 444.