short for Application software, also called an app, which is software for specific purposes. From version SharePoint 2013, apps was introduced.
Application software is all the computer software that causes a computer to perform useful tasks (compare with computer viruses) beyond the running of the computer itself. A specific instance of such software is called a software application, application or app.
From version SharePoint 2013, apps was introduced. Apps for SharePoint is globally available to enable download apps to a SharePoint farm enabled for apps downloads and use.
Microsoft have now renamed apps for SharePoint to SharePoint Add-ins.