Through the 1920s and 1930s,
the 1914–1918 war was generally known as The Great War.

"That was before we knew enough to number them."

Since the mid-1940s,
the 1914–1918 war has been generally known as World War One.

On monuments erected before 1940, it is called The Great War;
on later monuments it is called World War One.

In newspapers published in the 1940s, 1950s, and 1960s,
you will sometimes see references to The Kaiser War (1914-1918)
and The Hitler War (1939-1945).