Green’s Dictionary of Slang

calm n.

(UK Und.) a hat.

1738

Ordinary of Newgate Accounts 8 Nov. 🌐 He told Dr. Fluellin, he had seen a Tale, (a Sword) a Scout, (a Watch) a Calm and Shade, (a Hat and Wig) a Brace of Wedges, (Silver Buckles) and an outside Toge, (a Cloak).

In compounds

calm juice (n.)

(Aus.) a depressant.

1970

K. Mackey Cure 113: Into the dressing room and out with the outfit and plunge the clam juice into the blood, into the blood.