Decoration Day
2 of the 7 encyclopedias on this shelf carry an entry for Decoration Day. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
or Memorial Day , a day set apart for the decoration of the graves of soldiers who fell in the Civil War, and for the holding of commemorative exercises. This observance originated in the Southern States. It was copied in the North. In 1868 General John A. Logan, then commander-in-chief of the Grand Army of the Republic , issued a general order setting aside the 30th of May for the purpose of strewing flowers on the graves of old soldiers and for such exercises as local posts may direct. In many of the states that date is made a legal holiday. Owing to the earlier appearance of flowers in the South, April 26th is set apart as Confederate Memorial Day by Alabama, Florida, Georgia, and Mississippi, and May 10th by North and South Carolina . It is now customary, both North and South, to decorate the graves of soldiers regardless of the side on which they fought. Credit for this beautiful courtesy belongs to the women of the South. See Arbor Day ; Holiday
Collier's New Encyclopedia (1921)
a day set apart for decorating the graves of soldiers and Civil sailors who fell in the American War (1861-1865) and in other wars. The practice of setting aside a day to visit the graves of the fallen soldiers recall the memory of their noble deeds, and strew their tombs with flowers, took its rise early in the Civil War; first in particular places, here a city, there a village, or it might be a county. In time, many State Legislatures were induced to make a given day a legal holiday for this purpose, and the President and governors were led to unite in recommending the observance of the same day (May 30), now known as "Decoration Day," in every State of the Union. In the Southern States various days in April are set apart for decorating the graves of the Confederate dead, and the name "Memorial Day" is more commonly used there than Decoration Day.