Machine Learning (ML) is a subset of artificial intelligence (AI) that focuses on building systems that learn, or improve performance, based on the data they consume. Artificial intelligence is a broad term that refers to systems or machines that mimic human intelligence. Machine learning is how they do it.
The term "Machine Learning" was coined in 1959 by Arthur Samuel, an American IBMer and pioneer in the field of computer gaming and artificial intelligence.
Machine learning algorithms are now used in a wide variety of applications, such as in email filtering and computer vision, where it is difficult or unfeasible to develop conventional algorithms to perform the needed tasks.