通过查询《元照英美法词典》得出：

absolute deed 对应的中文是“无条件契据”，指不附加任何限制条件或废除条件的契据，相对于抵押契据〔mortgage deed〕而言。

mortgage deed对应的中文是“抵押契据”。

具体含义可参考二者的英文释义：

An absolute deed is a legal document transferring all the ownership rights of a property from the seller to the buyer without any conditions. It is an outright transfer of property ownership, implying that the seller relinquishes all rights, titles, and interests in the property.

大意是，无条件契据，指的是一份法律文件，无任何条件地将物业的所有权利从卖方转移给买方。这是物业所有权的彻底转让，意味着卖方放弃了对物业的所有权利、所有权和利益。

A mortgage deed is a legal document that secures a loan on a property by serving as a lien against the property until the mortgage is paid off. It outlines the rights and obligations of both the borrower and the lender, including the borrower's responsibility to repay the loan and the lender's right to seize the property if the borrower fails to meet the repayment terms.

大意是，抵押契据，是一份通过作为物业的质押权利而确保贷款的法律文件，直到抵押贷款被偿还为止。它概述了借款人和贷款人的权利和义务，包括借款人偿还贷款的责任和借款人未能满足还款条款时贷款人收回物业的权利。