A biome is a huge kind of natural place, named by its usual weather and the plants that can live there — and with them, the animals that belong there too. Desert. Rainforest. Tundra. Grassland. Each of those is a biome. The word does not mean one pond or one hill; it is a pattern that can stretch across countries. Scientists group the living world this way so they can talk about similar places together. You will meet it in school geography and biology, in a formal textbook voice. Though actually the tidy list is tidier than the land: the edges blur, people argue about how many biomes there are, and animals are part of the picture even when a short definition only mentions weather and plants. An ecosystem can be small. A biome is the big type.