Is Bitcoin considered an ETF?

Could you please clarify for me whether Bitcoin is classified as an Exchange-Traded Fund (ETF)? I've heard different opinions on this matter and I'm quite confused. ETFs are known for tracking a basket of securities or a particular index, but Bitcoin being a digital currency, does it fit into this category? Or is it seen more as a commodity or a standalone investment? I'm interested in understanding the distinction and how it impacts investors' strategies. Thank you for your assistance.