What is the main reason the Sun retained a proper name like 'the Sun' while other stars were given general classifications?

Answer

Historical development and local perspective.

The habit of using the proper name stems from ancient observers studying the Sun as the only star directly affecting their lives and appearing to move daily, leading to a unique designation long before its identity as one star among billions was understood.

What is the main reason the Sun retained a proper name like 'the Sun' while other stars were given general classifications?
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