Machine Learning, Deep Learning, and AI: What's the Difference?

You hear a lot of different terms bandied about these days when it comes to new data processing techniques. One person says they're using machine learning, while another calls it artificial intelligence. Still others may claim to be doing deep learning, while "cognitive" is the favored phrase for some. What does it all mean? While many of these terms are related and can overlap in some ways, there are key differences that can be important, and that could be a barrier to fully understanding what people mean when they use these words (assuming they're using them correctly).