Engl. law. The union of securities given at different times, so as to prevent any intermediate purchasers claiming title to redeem, or otherwise discharge one lien, which is prior, without redeeming or discharging other liens also, which are subsequent to his own title. 2. It is an established doctrine in the English chancery that a bona fide purchaser and without any notice of a defect in his title at the time of the purchase, may lawfully buy any statute, mortgage, or encumbrance, and if he can defend by those at law, his adversary shall have no help in equity to set those encumbrances aside, for equity will not disarm such a purchaser. And as mortgagees are considered in equity as purchasers pro tanto, the same doctrine has extended to them, and a mortgagee who has advanced his money without notice of any prior encumbrance, may, by getting an assignment of a statute, judgment, or recognizance, protect himself from any encumbrance subsequent to such statute, judgment or recognizance, though prior to his mortgage; that is, he will be allowed to tack or unite his mortgage to such old security, and will by that means be entitled to recover all moneys for which such security was given, together with the money due on his mortgage, before the prior mortgagees are entitled to recover anything.
Law Dictionary – Alternative Legal Definition
The uniting securities given at different times, so as to prevent any intermediate purchaser from claiming a title to redeem or otherwise discharge one lien, which is prior, without redeeming or discharging the other liens also, which are subsequent to his own title. 1 Story, Eq. Jur.