theme

noun

Contains graphics and appearance information. Customizes the look and feel of the store. Magento can ship themes in (Composer) packages. But themes can be placed under app / design, which are not shipped in a package. Packages are the unit of download for Composer, and — via Magento Marketplace — Magento users can download CE or EE as a series of packages, where packages contain modules, themes, or language packs.