Why is it called Lazio?

Excuse me, but could you elaborate on the origins of the name "Lazio"? I understand it's a term associated with something, but I'm not quite clear on the etymology or the reason behind its adoption. Is it derived from a specific historical event, a geographical feature, or perhaps a cultural reference? It would be fascinating to learn more about the story behind this name and how it came to be associated with what it represents today.