sensei 先生

In Japanese, sensei 先生 means "teacher" most of the time. It can also mean "doctor," or refer to an artist or author, a "master" of arts. It's also a honorific, so it can come after the name of someone who's a teacher, doctor, artist, etc.

Manga: "Assassination Classroom," Ansatsu Kyoushitsu 暗殺教室 (Chapter 2)

• Kanji
• "Teacher"
• "Master"
• "Doctor"
• "Author," "Writer," "Artist"
• After Name
• せんせー

Kanji of Sensei

The kanji of sensei 先生 mean "previous," 先, and "life," 生.

Source: japanesewithanime.com (CC BY-SA 4.0)

In other words, sensei means literally "previous life," because your teacher is usually someone who is older than you, he's passing onto you knowledge of his life, the previous life.

• saki ni umareta hito 先に生まれた人
  Person [who] was born earlier.
  • saki 先 and umu 生む are read with the kun'yomi readings of the kanji while sensei 先生 has the on'yomi.

Of course, it's not always the case that your sensei is older than you, but that's just where the word comes from.

"Teacher" in Japanese

The word sensei 先生 can mean "teacher" in Japanese.

Manga: "Assassination Classroom," Ansatsu Kyoushitsu 暗殺教室 (Chapter 2)

• Context: a teacher talks to a student.
• sensei wa ne, Nagisa-kun
  先生はね　渚君
  Nagisa-kun, [about me], [you see]
  • In this line, the speaker is the teacher, the sensei.
  • So when he talks "about the sensei," he's talking about himself: "about me."
  • In Japanese, using titles in this way is uncommon, but possible.
• aru hito to no yakusoku wo
  mamoru tame ni
  kimi-tachi no sensei ni
  narimashita
  ある人との約束を守るために君達の先生になりました
  To keep a promise with a [certain] person, [I've] become your teacher.
  • kimi-tachi no 君達の
    Your. (plural. The teacher of you, and the rest of your class. See: pluralizing suffix.)

Note that there are also other words that can refer to teachers, for example:

• kyoushi 教師
  Teacher.
  • Who teaches in a:
  • kyoushitsu 教室
    Classroom.
  • Can also refer to a teacher as in someone who offers guidance in a:
  • kyoukai 教会
    Church.
  • senkyoushi 宣教師
    Missionary.
• katei kyoushi 家庭教師
  Family teacher. (literally.)
  Private tutor.
• tan'nin kyoushi 担任教師
  tan'nin no sensei 担任の先生
  Teacher in charge.
  • The teacher who's in charge of a classroom, also known as "homeroom teacher."
• kyouin 教員
  Faculty member.
  • Any "educator" from grade school to high school.
• kyouyu 教諭
  Licensed teacher.
  • Someone with a license to teach in a school.
• kyouju 教授
  Professor.
  • Specially of an university, or college, daigaku 大学, as opposed to high-school and below.
• hakase 博士
  Professor. PhD. Doctor.
  • In anime, these are often researchers, inventors, scientists, not teachers.

"Master" in Japanese

The word sensei 先生 may also refer to a "master," in the sense that they're an expert in their field or craft and you can learn from them, even if they aren't in fact officially teaching anyone as a normal teacher would.

Manga: Majin Tantei Nougami Neuro 魔人探偵 脳噛ネウロ (Chapter 1)

• Context: just... just focus on the dialogue, okay?
• boku wa joshu deshu!!!
  僕は助手です！！
  I'm an assistant!!
• kono meitantei
  Katsuragi Yako-sensei no!!
  この名探偵桂木弥子先生の！！
  Of this famous detective, Katsuragi Yoko-sensei!!
  • Here, sensei is an honorific. (explained further below.)
  • She's a famous detective, because of her incredible detective skills, so she's addressed as a "master" of her craft.
  • The no の at the end turns the noun into a no-adjective, which normally qualifies what comes after it, but, in this case, it qualifies joshu, which is in a previous sentence.
  • sensei no joshu
    先生の助手
    Sensei's assistant.
    Assistant of sensei.

Of course, there are also other words for "master" in Japanese, like:

• shishou 師匠
  Master. (e.g. of martial arts.)
• goshujinsama ご主人様
  A retainer's lord.
  A slave's master.
  A pet's owner.
  A shop's owner.
  A woman's husband.
• masutaa suru マスターする
  To master. (a skill.)

"Doctor" in Japanese

The word sensei 先生 may also refer to a "doctor."

Manga: MONSTER (Chapter 7)

• Context: patient in wheelchair talks to their doctor.
• sensei
  先生
  Doctor...
• sensei to ore,
  anmari toshi
  chigawanai kedo............
  先生と俺、あんまり年違わないけど････････････
  [You] and me, [our] ages don't differ much, but.........
  • We're about the same age, but...
• sensei...... oyaji mitai da.
  先生･･････親父みたいだ。
  [You]...... are like [my] father.

Note that there are other words used to refer to doctors, for example:

• isha 医者
  Doctor.
• oishasan お医者さん
  Doctor. (polite variant.)
• ishi 医師
  Doctor (certified.)
  • The difference between ishi 医師 and isha 医者 is that an isha is a "doctor" in the sense that they're treating patients, while ishi 医師 is literally a "master of medicine."
  • That is, ishi 医師 puts emphasis on knowledge and expertise, and, perhaps most importantly, on their medical certification, their medical license.
  • In manga, sometimes you have black market doctors who don't have a license but go around treating people. Those would be isha, but not ishi.

"Author," "Writer," "Artist" in Japanese

The worse sensei 先生 can also refer to authors, writers of fiction, novels, and artists, painters, illustrators, etc.

In the manga and anime Bakuman バクマン, for example, Ashirogi Mutou 亜城木 夢叶 is the pen name used by the two main characters on the manga they author. It's not even a real name, it's just a pseudonym. Even so, they are still called Ashirogi-sensei 亜城木先生 by other characters in the series because their skill and knowledge in the field has been deemed real.

Note that, again, there are other words for this stuff:

• sakka 作家
  Author.
• shousetsu-ka 小説家
  Novelist. Fiction writer.
  • Writes:
  • shousetsu 小説
    Novel.
• manga-ka 漫画家
  Manga artist.
• ga-ka 画家
  Painter.
• irasutoreetaa イラストレーター
  Illustrator.

Honorific

When sensei 先生 comes after a person's name, it means that person is a sensei. That is: that person is a teacher, or a doctor, or an artist, or a writer, etc. For example:

• watashi no sensei 私の先生
  My teacher.
  • Here, sensei is a noun.
• Tanaka-sensei 田中先生
  Tanaka (who's a teacher.)
  Teacher Tanaka.
  • Here, sensei is a honorific.

• watashi no sensei wa Tanaka-san
  私の先生は田中さん
  My teacher is Tanaka-san.
• sensei ni osowatta koto wa isshou wasurenai
  先生に教わったことは一生忘れない
  The thing [that] teacher taught [me, I] will [never] forget.
  • sensei ni osowaru 先生に教わる
    To be taught by teacher.
  • isshou wasurenai 一生忘れない
    To not forget in one's whole life.
    To never forget.
• Tanaka-sensei ni osowatta koto wa isshou wasurenai
  田中先生に教わったことは一生忘れない
  The thing [that] Tanaka-sensei taught [me, I] will [never] forget.
  The thing [that] Tanaka (who's a teacher) taught [me, I] will [never] forget.
  The thing [that] teacher Tanaka taught [me, I] will [never] forget.

When this sort of thing happens, it's called a honorific. In Japanese, when a noun is used as a honorific, it means that person is that noun. This often happens with titles of professions. An example of another noun honorific:

• watashi no senpai 私の先輩
  My senior.
• Tanaka-senpai 田中先輩
  Tanaka (who's my senior.)

• Tanaka-hakase 田中博士
  Tanaka (who's a professor.)
  Professor Tanaka.
• Tanaka-shishou 田中師匠
  Tanaka (who's my master.)
  Master Tanaka.
• Tanaka-oniisan 田中お兄さん
  Tanaka (who's my older brother.)
  Big bro Tanaka.

せんせー

The word sensee せんせー is a distorted spelling of sensei. It means the same thing, it's just spelled differently, and likely pronounced more casually.

Manga: School Rumble (Chapter 3)

• sensee
  せんせー
  Teacher.
• nanda?
  なんだ？
  What is it?
• me ga warui node
  mae no seki to
  koukan shite
  hoshii-n-desu-ga
  目が悪いので前の席と交換してほしいんですが
  [I have poor eyesight] so [I] want to switch [with one of] the front seats.
  • me ga warui 目が悪い
    Eyes are bad. (literally.)
    To have poor eyesight.