Do Ut Des
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Lat. I give that you may give; I give [you] that you may give [me.] A formula in the civil law, constituting a general division under which those contracts (termed "innominate") were classed in which something was given by one party as a consideration for something given by the other.
Dig. 19, 4; Id. 19, 5, 5; 2 Bl. Comm. 444.