A bottleneck may refer to any of the following:
1. A bottleneck happens when too much information enters one source and causes a computer to slow down or become unresponsive. For example, a website could be mentioned on a popular page that causes a bottleneck because of all the traffic sent to the web server. In this bottleneck example, the visitors trying to visit the website would encounter errors or unusually slow load times.
2. A bottleneck is also the weakest or slowest stage of a program or algorithm.