“The relations of the cestui que trust with the trustee are in personam or ‘unital,’ and the same is true of a contract beneficiary and the promisor ….” William R. Anson, Principles of the Law of Contract 326 n.1 (Arthur L. Corbin ed., 3d Am. ed. 1919).
unital
unital (yoo-n[schwa]-t[schwa]l), adj. Of or relating to legal relations that exist between only two persons. Cf. MULTITAL.