Every volume (disk), application, file, and folder on your Mac is represented by an icon.

Icons look like the item that they represent. For example, your hard disk volume icon (Macintosh HD) looks like a hard drive, a text document looks like a piece of paper, and a folder icon looks like a folder where you store papers.

App icons are all generally unique, so they stand out from one another.

Folders contain other files, like your documents or apps. Certain folder icons help you identify what's inside of them, such as apps, documents or music.