The word is probably derived from the ancient Flemish coin, a plaquette, in use before the introduction into the Netherlands of the French money reckoned by francs and centimes. It can be found in the works of Robert Burns too: Nae howdie gets a social night, or plack frae them (Scotch Drink) Stretch a joint to catch a plack, Abuse a brother to his back. (To Gavin Hamilton) See also Bawbee Bodle Pound Scots Scottish coinage References MacKay, Charles – A Dictionary of Lowland Scotch (1888) Coins of Scotland