A wetland is land that is soaked with water — either covered by shallow water or wet mud most of the year. Marshes, swamps, bogs, tidal flats, and the muddy edges of rivers and lakes are all wetlands. It is the in-between kind of place: not dry ground you can build on, not deep water you can sail on. You will very often see it in the plural, wetlands, even for a single area: "the wetlands near the river". It is a slightly technical word — the everyday words are marsh, swamp, or in Taiwan often just 濕地 — and it belongs to science, conservation, and government writing. That is because wetlands matter: they hold birds and fish, soak up floodwater like a sponge, and clean water as it passes through, so they are protected by law in many countries and by an international agreement called the Ramsar Convention. Taiwan has famous ones, such as Guandu and the Gaomei wetlands. The word is also used as an adjective before a noun: wetland birds, wetland conservation, a wetland park.