Subrogate(v. t.) To put in the place of another; to substitute.
Subrogation(n.) The act of subrogating.
Subrogation(n.) The substitution of one person in the place of another as a creditor, the new creditor succeeding to the rights of the former; the mode by which a third person who pays a creditor succeeds to his rights against the debtor.

Words within subrogation