**Half-mast** is the maritime term for a flag lowered from the truck as a mark of mourning or respect; ashore the equivalent is half-staff in American usage, half-mast or half-staff interchangeably in British. The flag is hoisted to the top and then lowered the depth of one flag, the exact distance varying by national custom. The practice originated in the seventeenth century as a sign that an ‘invisible flag of death’ flew above.
**Example**: A Royal Navy warship flies its ensign at half-mast upon the death of the Sovereign, until the proclamation of the successor.
**See also**: [half-staff](/glossary/half-staff/), [full-staff](/glossary/full-staff/), [ensign-at-sea](/glossary/ensign-at-sea/), [lowering](/glossary/lowering/)