Named after Giulio Cesare Lagalla - Italian philosopher (1571-1624).
Lagalla is the remnant of a lunar crater. Wilhelm partly overlies the northeastern rim, and Montanari is attached to the southeast. The remainder of the rim is heavily eroded, with small craters overlaying sections along most of the sides. The rim is nearly nonexistent to the south, and the most intact portion is along the northwest. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.