Latin, hevewarda, custodia.
There are four references in Domesday Book to the customary obligation of providing a bodyguard, two in Kent (custodia) for the king, and two in Cambridgeshire (hevewarda) for the sheriff. It is difficult to believe that the obligation was not far more common, though it was perhaps supplied in part by customary escorts. But these, too, are recorded unsystematically.
For more detail, see Paul Vinogradoff, English society in the eleventh century: essays in English medieval history (1908); and N. Nielson, Customary rents (1910).