What is done, appointed by, or founded on, a testament, or will; as, a testamentary guardian of a minor, who may be appointed by the will of a father to act in that capacity until the child becomes of age called?

testamentary — Done, appointed by, or founded on, a testament, or will; as, a testamentary guardian of a minor, who may be appointed by the will of a father to act in that capacity until the child becomes of age. (Webster's 1913.)