Montes Carpatus is a mountain range that forms the southern edge of the Mare Imbrium. This rugged range generally stretches from west to east. The western end begins in the vicinity of the crater T. Mayer, although a few low ridges curve northwards towards Euler crater. (wikipedia entry)
A mons is a mountain. On the Moon they are named after terrestrial mountain ranges, nearby craters, and deceased scientists who have made outstanding or fundamental contributions to their fields.