From BiblePortal Wikipedia

Hawker's Poor Man's Concordance And Dictionary [1]

Son of Enoch. ( Genesis 5:21; Gen 5:27) This man attained the longest age ever recorded, even nine hundred and sixty-nine years. His name carries somewhat of an idea respecting it; one who demands his death, from Shelah, to demand; and Muth, death. Some derive Methusaleh from Sheol, grave. But the meaning in either sense is the same.