A taxonomy is a system for organizing and classifying things into groups based on their shared characteristics. Scientists use taxonomy to sort living things into categories like kingdom, phylum, class, order, family, genus, and species. For example, a house cat belongs to the kingdom Animalia, the class Mammalia, the family Felidae, and the species Felis catus.

The Swedish scientist Carl Linnaeus developed the modern system of taxonomy in the 1700s, creating a universal language that scientists worldwide still use today. Before his work, scientists in different countries used different names for the same plants and animals, making communication nearly impossible. His system gave every living thing a two-part Latin name (like Homo sapiens for humans) that scientists everywhere could recognize.

Taxonomy applies beyond biology to many fields of knowledge. Libraries use taxonomy to organize books into categories. Computer scientists create taxonomies to classify information on websites. Museums use taxonomies to arrange their collections.

When you organize your book collection by genre, or sort your trading cards by team and player position, you're creating your own simple taxonomy. The key is finding meaningful ways to group things so you can find what you need and understand how different items relate to each other.