What term describes a section of land that extends into the sea?

The term that describes a section of land that extends into the sea is "headland." A headland is characterized by its prominent point, typically formed by more resistant rock that has managed to withstand erosion better than surrounding areas. This geological feature often projects into the water, creating a distinct boundary between land and sea.

Headlands are significant in coastal geography as they can influence local currents and wave action, often resulting in varied ecosystems in the adjacent waters. Their formation is a natural consequence of the continual wearing down of softer rock by waves, while harder rock remains intact, leading to this projecting feature.

In contrast, the other terms refer to different aspects of coastal geography. The shoreline is the line where the land meets the sea, while the coastline generally refers to the overall outline of the land along the edge of the sea, including both landforms and water bodies. A bay, on the other hand, is a body of water partially enclosed by land, often between two headlands.