Someone that hikes to the tops of different mountains for bragging rights. Greater the number, greater the bragging rights.
As a peakbagger, he's at 79, but Joe over there has 107.
1) Typically grouped by state, mountain peaks that range from 13,000 to 13,999 feet in height.
2) Slang for a hiker that climbs to the peak of mountains that range from 13,000 to 13,999 feet in height.
That state as over 657 13'ers.
He's a 13'er trying to climb all the 13,000 plus mountains in the state.