A systematic shift in technology that changes and improves the way that business is done, while creating new businesses across all industries in the economy.
The first industrial revolution is the typical, steam-engine powered one. The second one comes about 1870 after a lull/plateau in production, and includes:
- Standardization in processes and parts to make industrial production and machinery easier and cheaper.
- The Bessemer process to make steel cheaper. Steel is a lot better than iron and still makes up a big chunk of infrastructure and transportation.
- The Telegraph.
The third one is computers and the internet, up to and including smartphones.
The fourth one is supposed to be coming, according to some economists, including stuff like AI, blockchain, bioimplants, etc.
Some economists talk about first revolution parts a and b, and second with two parts as well instead of 4.
Rephrasing of this EE video.