1The most basic Japanese honorific suffix, attached after a person's surname, given name, full name, or job title to show politeness and friendliness. Used regardless of gender or marital status, in school, work, shops, and everyday social contexts. Key rule: do not attach さん to your own name, your own family members, or your coworkers when speaking about them to people outside your group (say うちの田中, not うちの田中さん). The more formal alternative is 様 (-sama); ちゃん is used for children or close relationships; 君 (-kun) is typically used for younger or peer-level males.
田中さんは今日お休みです。
Mr./Ms. Tanaka is off today.
「鈴木さん」と呼ばれて、振り向いた。
I heard someone say 'Suzuki-san' and turned around.
すみません、店員さん、これください。
Excuse me—could I get this, please?
山田さん、この資料をお願いします。
Yamada-san, could you take care of these documents?
取引先には「うちの山田が伺います」、社内では「山田さん、お願いします」と言う。
To a client you say 'Our Yamada will come by' (no さん), but inside the company you say 'Yamada-san, please go ahead.'
2A suffix attached to nouns (people, animals, shops or professions, occasionally na-adjectives) that adds politeness, warmth, or a softening feel. Common patterns: terms for the listener's family or associates (お客さん, お子さん, 息子さん, 娘さん); friendly names for jobs or shops (八百屋さん greengrocer, パン屋さん bakery, お巡りさん police officer, お医者さん doctor); and occasionally personifying non-humans (神さん, お月さん—slightly Kansai-flavored). Note: use 〜さん for the other party's family, never your own (your own son is just 息子; only the listener's son is 息子さん).
お子さんは何歳ですか。
How old is your child?
お客さん、こちらでお待ちください。
Sir/Madam, please wait over here.
近所のパン屋さんで朝ごはんを買った。
I bought breakfast at the neighborhood bakery.
迷子になって、お巡りさんに道を聞いた。
I got lost and asked a police officer for directions.