Machine learning refers to a range of techniques to build systems that have the ability to learn and improve from experience, without being explicitly programmed to do so.
Two common examples of machine learning are supervised learning and reinforcement learning.
This is where a program is given data that has been labelled. From this, the program starts to recognise patterns, allowing it to predict or classify new information. Examples include image recognition, where programs are trained to recognise cats.
This involves giving the program feedback each time it performs a task, so that it learns from doing things correctly.