A peninsula, also known as a promontory, is a landform that extends out into water from a larger landmass. It is generally associated with being surrounded by water on three sides. Another word for peninsula could also be an isthmus. Depending on the shape of the landform, other similar terms could also be used. For instance, a headland is a narrow piece of land that extends out into the sea. A cape is a prominent headland that is usually higher than the surrounding terrain. Finally, a spit is a long, narrow landform that juts out into a water body and is formed by deposition of sediment.