The word Lappung (Lapung = Lampung) is an acronym for "melapung" (floating). According to sources, the origin of Lappung might have been based on:
1. That person who descended this Lampung tribe was umpu Serutting Satti who was believed to be insubmersible. According to another source, if he kept floating as he was diving. Therefore he was called Si Lappung (the floating man)
2. It is said that the tip of Sumatra Island was originally a region that seemed adrift at sea and was connected by a row of hills only.
The existence of the Lebu Sea (the lost ocean) was due to alluvial land that extended from northern Sumatra to the south. It was the land that used to be a shallow seabed.
If we see a row of mountains in Lampung, it appears elongated from north to south, turned east, continue to veer more to the north, and stopped at Mount Balak. Then the sight from the north gives an idea as if this area were a floating area.
Reference : Bahasa Lampung Book, Author : Herman.