What is the origin of the word plutonium?

It is named after the planet Pluto, which is, itself, named after the roman god of the underworld, Pluto. Pluto is the roman name for the Greek god Hades, which is the underworld itself.
Yes, it is named after the planet Pluto, however that is not the 'definition' of the word Plutonium itself. In 1994, the definition of the word Plutonium was given as "the element of the Lord of Hell'. It seems that this 1994 definition has all but disappeared from public view. It makes one wonder why.