the.com/dear

means A word used to address someone with warmth or formal politeness, especially at the start of a letter, or to describe someone cherished or costly.

from From Old English 'deore,' meaning precious or costly — the same root gives us 'darling.' The sense split early: something dear could be beloved, or simply expensive, and English kept both meanings running side by side. The letter-opening use ('Dear Sir,' 'Dear Madam') grew from that 'precious' sense, politely pretending the recipient is cherished even when what follows is a bill, a complaint, or a request for unpaid favors.