broad arrow

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An arrow with a wide barbed head.
• noun Chiefly British A wide arrowhead mark identifying government property.

from The Century Dictionary.

• noun The royal mark of British government stores of every description, which it is felony to obliterate or deface.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an arrowhead mark identifying British government property
• noun a mark shaped like an arrowhead; used to mark convicts' clothing
• noun an arrow with a wide barbed head