Is Dot and Polkadot the same?

I'm curious about a point here: Are Dot and Polkadot interchangeable terms, or do they have distinct meanings? This seems like a fundamental question in the cryptocurrency world, especially given the buzz surrounding Polkadot. If they are the same, why do we have two names for the same thing? And if they're not, what are the key differences between them? I'm eager to understand this distinction, as it could have significant implications for investors and enthusiasts alike. Could you please clarify this for me?