Pam I've entered this late but the 'official' (but that does not means it was always adhered to) abbreviations for a muster are: D = Discharged; DD = Discharged Dead; DS = Discharged to sick quarters; DUS = Discharged unserviceable; DQ = discharged but under query (pending one of the other categories); Run = deserted. Having said this, if it is on his enlistment (where did you get this?) and is only followed by a date, I'd be inclined to think it was just "Discharge Date" on that date. Is there any evidence that he was alive subsequently? It would be more normal, if it was Discharged Dead, to be additionally qualified by something like "at sea"; "slain in battle"; "fell from aloft"; "disease"; etc. For the truth, you will need to find the Muster List and/or Pay Book for the last ship on which he served for the real detail... but I guess you do not know any ship details. See PRO Handbook No. 22 - Naval Records for Genealogists by N A M Rodger; it is the best source for interpreting RN records. John LOVE, from a long line of seafarers.