Flags are flown at half-staff or half-mast as a sign of mourning, respect, or remembrance, and the custom most likely grew out of early 17th-century maritime practice. The oldest widely cited origin points to a British ship in 1612 that lowered its flag after the death of its captain, with later tradition saying the space above the flag was left for an “invisible” flag of death.
Shipboard beginnings
The terms are often used interchangeably, but there is a practical difference: “half-mast” is the nautical term for ships, while “half-staff” is used for flags on land. The gesture was easy for sailors to recognize from a distance, which helped it spread as a solemn signal long before it became a formal civic custom.
Why it became a mourning symbol
Lowering the flag visually suggests that a nation, institution, or community is dimmed by loss. That symbolic meaning is now the main reason flags are lowered in many countries, especially after the death of national leaders, public servants, or during memorial observances.
Formal rules in practice
In the United States, the practice was standardized over time and is now guided by the U.S. Flag Code and presidential proclamations. The flag is typically raised fully to the top first, then lowered to the half-staff position, and raised back to the top before it is taken down at the end of the day. Different deaths and memorial days trigger different periods of display, which is why flags sometimes appear at half-staff on one day and not the next.
A lasting symbol
What started as a maritime signal became a universal public language for grief. Even today, half-staff remains one of the clearest ceremonial gestures a country can make without saying a word.