Half-mast or half-staff refers to a flag flying below the summit of a ship mast, a pole on land, or a pole on a building. In many countries this is seen as a symbol of respect, mourning, distress, or, in some cases, a salute.
The Finnish flag flying at half-mast after the 2011 Norway attacks
The American flag flying at half-mast in Buchenwald, Thuringia, Nazi Germany, on 19 April 1945 after the death of US President Franklin Roosevelt
The Australian White Ensign flying at half-mast. In accordance with British tradition, the flag is flying only one flag's width below the top of the pole.
The Brazilian flag flying at half-mast beside the Mercosul flag in front of the National Congress of Brazil in memory of the victims of the Chapecoense crash on 29 November 2016
Mourning is the expression of an experience that is the consequence of an event in life involving loss, causing grief, occurring as a result of someone's death, specifically someone who was loved, although loss from death is not exclusively the cause of all experience of grief.
Girl in a mourning dress holding a framed photograph of her father, who presumably died during the American Civil War
Egyptian women in a sorrowful gesture of mourning
Empress Amélie of Brazil wore black in mourning for her husband Pedro I for the rest of her life.
Japanese funeral arrangement