Definition of coal box in English:

coal box

Pronunciation /ˈkəʊl bɒks/

noun

  • 1A box for holding coal for a (domestic) fire; a coal scuttle.

  • 2British military slang, historical A low-velocity shell emitting black smoke, used by the German army during the First World War (1914–18); = "Black Maria".

Origin

Early 18th century; earliest use found in Rules Army in Ireland. From coal + box.