Proper noun
Grand Army of the Republic
(now historical) An organisation for veterans of the US Army, Navy and Marines who served in the American Civil War.
By proclamation of General John A. Logan of the Grand Army of the Republic, the first major Memorial Day observance was held to honor those who died in the Civil War. Source: Internet
In 1886, a group of veterans established a post of the Grand Army of the Republic in Barton in his name. Source: Internet
It was originally established by the veterans of the Grand Army of the Republic (the Union Army) to commemorate their fallen Civil War comrades. Source: Internet