A taxon (plural: taxa) is a group of living things that scientists have classified together because they share important characteristics. When biologists organize life on Earth, they create categories at different levels: species, genus, family, order, class, phylum, and kingdom. Each of these levels is a taxon.

For example, dogs are a species (one taxon), but they also belong to the genus Canis (another taxon), the family Canidae (yet another taxon), and so on up the ladder. Your cat, your teacher, an oak tree, and a mushroom each belong to multiple taxa depending on how zoomed in or zoomed out you look.

The word helps scientists be precise when talking about groups of organisms. Instead of saying “the group of all mammals,” a biologist might say “the taxon Mammalia.” Instead of “birds,” they might say “the taxon Aves.”

Think of taxa like nested boxes: small boxes (species) fit inside medium boxes (genera) that fit inside larger boxes (families), and so on. When scientists discover a new creature, one of their important jobs is figuring out which taxa it belongs to, which tells us how it relates to other living things.