Credit Support Deed
May refer to the 1995 ISDA Credit Support Deed (Security Interest - English Law), a credit support arrangement under which parties establish bilateral mark-to-market collateral arrangements relying on a formal English law security interest over collateral transferred in the form of securities or cash. It is a stand-alone document (that is, not simply an annex to the Schedule), but is otherwise comparable to the 1994 NY Law CSA for use with New York law ISDA Master Agreements (which also relies on the creation of a formal security interest in the collateral).
It may, of course, refer to something else as well. But isn't really likely to.