killer app

The application that actually makes a sustaining market for a promising but
under-utilized technology. First used in the mid-1980s to describe Lotus
1-2-3 once it became evident that demand for that product had been the major
driver of the early business market for IBM PCs. The term was then
retrospectively applied to VisiCalc, which had played a similar role in the
success of the Apple II. After 1994 it became commonplace to describe the
World Wide Web as the Internet's .