Vallis Alpes is a lunar valley feature that bisects the Montes Alpes range. The valley is narrow at both ends and widens to a maximum width of about 10 km along the middle stretch. The valley floor is a flat, lava-flooded surface that is bisected by a slender, cleft-like rille. (wikipedia entry)
A vallis is a valley. On the Moon they are named after nearby craters or other landforms.