Probably miscaptialized it, but l == pounds (from libra), s == shillings (for solidus), d == pence (for denarius). It's the old monetary system in the UK before 1970-something. Maybe 1969. First saw the term in Finnegans Wake. I don't think I heard my dad use the term, but by then the other LSD had taken hold of the public's imagination. 12 d to the shilling, 20 shilling to the pound, 21 to the guinea. Pound is also called a quid, shilling a bob. There used to be a 10-bob note (which Mean Mr Mustard had up his nose), now there's a 50 p coin. Prices used to be written with a slash (or virgule) for the shilling: e.g., 5/6 (pronounced 5 and 6) for 5 shilling, 6 pence.