What do you call an area of land that is completely surrounded by water?

An area of land that is completely surrounded by water is referred to as an island. Islands are landforms that protrude from water and can vary greatly in size, from small sandbars to large land masses like Greenland. Their classification as islands is defined by their total encirclement by water, making them unique geographical features.

In contrast, peninsulas are landmasses that are surrounded by water on three sides but remain connected to the mainland. Atolls are ring-shaped coral reefs that encircle lagoons, and while they can also be considered land in water, they are specifically related to coral formations rather than being a generic landmass. Deltas form at the mouths of rivers where they deposit sediment, creating new land but are not surrounded by water on all sides. These distinctions help clarify why an island is the term used for land fully bordered by water.