Category theory is a branch of mathematics originally developed to transport ideas from one branch of mathematics to another, e.g. from topology to algebra. Applied category theory refers to efforts to transport the ideas of category theory from mathematics to other disciplines in science, engineering, and industry.
To learn more:
- What is applied category theory? – notes by Tai-Danae Bradley.
- Seven Sketches in Compositionality: An invitation to applied category theory – book by Brendan Fong and David Spivak (printed version available here).
See also Resources.