A catalog is an organized list of items, often with descriptions and details about each one. Libraries use catalogs to help you find books: you can search by title, author, or subject, and the catalog tells you exactly where to find what you're looking for on the shelves. Companies create catalogs showing products they sell, with pictures and prices so customers can browse and order. A seed catalog might list hundreds of varieties of tomatoes, beans, and flowers, describing how each one grows and what it needs.

Before computers, library catalogs used paper cards filed in wooden drawers. Today, most catalogs are digital databases you search on a screen.

Catalog can also work as a verb, meaning to organize items into a catalog. A museum might catalog its entire collection of paintings, recording each artist, date, and condition. Scientists catalog newly discovered species. When you catalog something, you're creating a systematic record so nothing gets lost or forgotten and anyone can find specific items later. Whether you're organizing a baseball card collection or a university research library, you're doing the same essential work: bringing order to information.