The Titans are the first family of gods in Greek stories — the ones who ruled the universe before Zeus. They were imagined as giants: shaped like people, but enormous. The story goes that Cronus led them, that he was warned his own child would replace him, and that Zeus, that child, grew up and led a war against them. The Titans lost, and the younger gods took over the sky. That fight is called the Titanomachy, and it is the reason so many English words about size come from this family. Some individual Titans stayed famous on their own: Atlas, who holds up the sky on his shoulders, and Prometheus, who stole fire and gave it to human beings. The word is normally plural and capitalised when it means these gods. Outside myth, people use "titans" with a small t for the biggest players in a field — the titans of Wall Street — and American sports teams borrow the name too. So the same word can be ancient gods, powerful business people, or a football team, and the capital letter plus the sentence around it tells you which.