Moraine, muh RAYN, is an accumulation of rocks, dirt, and other earth material that a glacier deposits when the ice melts. Moraine also means a band of such material in a glacier or on its surface, or an uneven ridge of material deposited at the edge of the melting ice. On each side of a glacier in a mountain valley are rock fragments that have rolled onto the ice from nearby slopes. These rock fragments form a lateral moraine.