Runway is like a big fancy show where models walk on a long path called a runway, and show off clothes and accessories made by fashion designers. Think of it like a really cool fashion parade for grown-ups! People who work in fashion get to see what's new and exciting, and then they might buy these clothes to sell in their own stores, or write about them in magazines. Some of these fashion shows are held in special buildings called fashion weeks, and they happen in cities like New York, Paris and Milan. It's kind of like a really, really fancy dress-up party, where everyone is looking at the models in their beautiful clothes and saying, "Ooh, I love that dress! I want one!"