A "killer app" is jargon in the computer industry for an application program that intentionally or unintentionally gets you to make the decision to buy the system the application runs on. A classic example of a killer app was the spreadsheet program, the first of which was called VisiCalc, followed later by Lotus 1-2-3. The spreadsheet application helped introduce the personal computer into the department level of large and small businesses. A killer app can refer to a generic type of application that hasn't existed before, to a particular product that first introduces a new application type, or to any application with wide appeal