A moment of silence is a period of silent contemplation, prayer, reflection, or meditation. Similar to flying a flag at half-mast, a moment of silence is often a gesture of respect, particularly in mourning for those who have died recently or as part of a tragic historical event.
Silent prayer, including moments of silence practiced during other group activities, have been practiced by Quakers for more than 300 years. Since silence contains no statements or assumptions concerning beliefs and requires no understanding of language to interpret, it is more easily accepted and used than a spoken prayer or observance when persons of different religious and cultural backgrounds participate together. In the colonial period Pennsylvania Quakers and Americans worshiped silently together on occasions, yet both groups thought that this implied that they had altered their traditional belief system in doing so. Over time, the effectiveness of Quaker-style silence for non-sectarian and non-controversial public observances has led to its almost universal use in the English-speaking world as well as other plural societies. This is also the case within many institutions where diverse groups are expected to participate but not necessarily share beliefs such as in government, schools, businesses and the military.
Many people in the Commonwealth of Nations observe a moment of silence, often two minutes, at 11:00am on November 11 each year (Armistice Day) to remember sacrifices of members of the armed forces and of civilians in times of war. The period of silence is essentially a ritualized night vigil bracketed by the traditional bugle call "The Last Post"" and "The Rouse", which is also called "Reveille" in the United States. The Last Post was the traditional bugle call at the end of the day, and the Rouse started the military day. For military purposes, the traditional night vigil over the slain was not just to ensure they were indeed dead and not unconscious or in a coma, but also to guard them from being mutilated or despoiled, or dragged off by scavengers. This makes the ceremony not so much an act of remembrance but a pledge to guard the progress of war death. The act is enhanced by the use of dedicated cenotaphs (literally Greek for "empty tomb") and the laying of wreaths—the traditional means of bestowing high freedoms in Ancient Rome. Some schools and colleges across the UK often sound the school bell or fire alarm to start and end the period of silence, similar to when Israel sound an air raid siren during the two minute silence.