The word "sir" has several interpretations.

(1)[ Mr.]

(2) Customary honorifics are usually used after a man's surname.

Talk to Mr. Du

(3) Call someone else's husband or the opposite person your husband.

(4) people who used to be bookkeeping.

Be a gentleman in the company

(5) People who used to tell stories, read physiognomy, calculate divination and watch geomantic omen.

Fortune teller

(6) Respect for elders

Prince Heshuo called him Meihualing, Mr. Qingquan.

(7)[ teacher]

Teach the teacher the scriptures. -Qing Yuanmei's "Sacrificing Sister"

[Doctor]: Doctor