What is the difference between concrete and cement?

You probably use the terms interchangeably, but “concrete” and “cement” do not mean the same thing.
Cement is one of the ingredients that makes concrete. The other ingredients are air, water, fine sand, and gravel or crushed stone. Through a process called “hydration,” the mixture hardens, and continues to harden for years after it’s dry. 

It’s not accurate, then, to call your sidewalk, patio or block walls “cement.” They’re concrete.
Another term you might use during a conversation about concrete is “masonry.” Masonry is an umbrella term that covers all building materials that you would typically bind together with mortar, like concrete blocks, adobe, stone and brick.