What is the name for the pile of rocks and debris left behind a glacier?

The term for the pile of rocks and debris left behind a glacier is "moraine." As a glacier moves, it erodes the underlying bedrock and picks up sediments and debris from the surrounding landscape. When the glacier retreats, it deposits this accumulated rock and sediment in various formations known as moraines. These can be categorized into several types, such as terminal moraines, which mark the furthest advance of the glacier, and lateral moraines, which are found along the sides of the glacier.

The other options refer to different geographical features: an iceberg is a mass of freshwater ice that has broken off from a glacier or ice shelf and floats in open water; a col is a low point or pass in a mountain range; and a fjord is a deep, narrow, and typically serpentine inlet of the sea between high cliffs or steep slopes, formed by the submergence of a glaciated valley. Therefore, the correct terminology for the debris left by a glacier is precisely "moraine."