The name Methuselah in the Bible
Methuselah is the son of Enoch, who famously walked with God, and the father of Lamech the Second and the grandfather of Noah (Genesis 5:25). He is also the man with the longest life-span in the Bible (969 years). The Bible doesn't actually mention it but a little arithmetic reveals that Methuselah died in the year of the great flood. The question of whether he died of natural causes or drowned remains unanswered.
And since Methuselah is an ancestor of Christ, he is also mentioned in the Greek New Testament, spelled as Μαθουσαλα (Mathousala) (Luke 3:37).
Etymology of the name Methuselah
The name Methuselah consists of two elements. The first part is מת (mat), which is either one of a few words to denote man or mankind, and used most often to indicate a male capable of combat, or it comes from the similar verb מות (mut) meaning to kill or die:
The second part comes from the verb שלח (shalah) meaning to send or let go:
For a meaning of the name Methuselah, Jones' Dictionary of Old Testament Proper Names reads מות (mut) for the first part and translates the whole name with When He Is Dead It Shall Be Sent. NOBSE Study Bible Name List and BDB Theological Dictionary both read מת (mat) for the first part; NOBSE translates the whole name with Man Of A Javelin; BDB proposes Man Of The Dart.
Perhaps less dramatic is Man Sent Out, that is Man With A Mission or simply: Missionary.