(1) A special method of distributing and installing software (or software upgrades) to a computer. For example, on a Macintosh computer, a package usually means "software." It's specifically a directory, presented as a single file, that contains all the information the Mac OS X Installer application needs to install your software. That includes the software itself, as well as files that are used only during the installation process. In a Windows environment it is sometimes called an installation package or update package.
(2) Multiple software programs that work together (or performs similar functions) and is bundled and sold together as a software package.