5 Types of Icons in OS X Yosemite Finder
Application icons are programs — the software you use to accomplish tasks on your Mac.
Mail, Safari, and Calendar are applications. So are Microsoft Word and Adobe Photoshop.
Application icons come in a variety of shapes. For example, application icons are often square-ish, diamond-shaped, rectangular, or just oddly shaped.
Document icons are files created by applications.
Letters created with TextEdit are documents. This article began life as a document created in Microsoft Word. And spreadsheet, PDF, video, image, and song files are all documents.
Document icons are often reminiscent of a piece of paper.
Folder icons (along with disk icons) are the Mac’s organizational containers.
You can put icons — and the applications or documents they stand for — in folders or disks. You can put folders in disks or in other folders.
Folders look like, well, manila folders (what a concept) and can contain just about any other icon. You use folders to organize your files and applications on your hard drive. You can have as many folders as you want, so don’t be afraid to create new ones. The thought behind the whole folders thing is pretty obvious: If your hard drive is a filing cabinet, folders are its drawers and folders (duh!).
Disk icons (along with folder icons) are the Mac’s organizational containers.
Remember that you can put folders in disks or in other folders, but you can’t put a disk inside another disk. And while disks behave pretty much like folders, their icons often look like disks.
Alias icons are wonderful — no, make that fabulous — organizational tools.
An alias is a tiny file that automatically opens the file, folder, disk, or network volume that it represents. Although an alias is technically an icon, it’s different from other icons; it actually does nothing but open a different icon when you double-click. Put another way, aliases are organizational tools that let you store an icon in more than one place without creating multiple copies of the file.