Original: A Munro is a mountain in Scotland with a height over 3000 f/O. They are named after Sir Hugh Munro, 4th Baronet (1856 - 1919), who produced the first list of such hills, known as Munros Tables, in 1891.
Simplified: They are named after Sir Hugh Munro (1856 - 1919), who produced the first attempt at a catalogue of such hills, known as Munro's Tables, in 1891.