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Japanese Family Vocabulary: Kinship Terms and the お-Prefix Asymmetry

Japanese family vocabulary splits most close relations into two words: a plain in-group form for your own family (父, chichi) and an honorific form for someone else's family (お父さん, otōsan).1 Once an N5 learner understands that split, the kinship list stops feeling arbitrary.

Overview​

Japanese family vocabulary rests on a small core list and one structural surprise. Learn the surprise first, and the list becomes a system rather than a pile of words.

The word 家族 (kazoku) and 親戚 (shinseki)​

家族かぞく (kazoku) means the immediate family or household unit. It is the core N5 word most learners come for.2 親戚しんせき (shinseki) means the wider circle of relatives, or extended kin, and is distinct from 家族.3

The honorific form for someone else's family is 御家族ごかぞく (go-kazoku). It is built with the ご- beautification prefix. Use it to refer to someone else's family.24

私わたしの家族かぞくは四人よにんです。2
"There are four people in my family."

御家族ごかぞくはお元気げんきですか。2
"Is your family well?"

家族 is N5; 親戚 is typically placed above N5 and is included here as reference.5

Two sets of words, one family​

For most close relations, Japanese keeps two words. Use a plain in-group form to refer to your own family member when speaking to outsiders. Use an honorific form (お…さん) for someone else's family member, and to address your own.142

The pairing is governed by uchi-soto (内/外, in-group / out-group), not by a separate humble-keigo verb system. In-group referents do not take honorifics when you speak to an outsider. That is why your own father is the bare 父, while another person's father is the honorific お父さん.1

The four core pairs are 父 / お父さん, 母 / お母さん, 兄 / お兄さん, and 姉 / お姉さん.42 Younger siblings 弟・妹 and several other terms do not form a clean お…さん honorific pair in the same way; see the list section.

The plain forms are not "humble keigo"

Many learner resources call 父, 母, and 兄 "humble." They are unmarked in-group reference forms, not formal 謙譲語けんじょうご (kenjōgo) verbs. The deferential effect comes from the uchi-soto rule, which strips honorifics off in-group referents. It does not come from the word itself.1

The own-family vs other-family asymmetry​

This is the rule that defines the page. Once the in-group / out-group boundary is clear, every two-word pair in the list follows the same rule.

The in-group (plain) forms: 父, 母, 兄, 姉, 弟, 妹​

These are the forms used to refer to your own family member when speaking to someone outside the family.12

RelationPlain (own, to outsider)ReadingRomaji
father父ちちchichi2
mother母ははhaha2
older brother兄あにani2
older sister姉あねane2
younger brother弟おとうとotōto2
younger sister妹いもうとimōto2

These forms are plain and neutral, not formal humble keigo. They can feel deferential because the uchi-soto rule removes honorifics from in-group referents in front of an outsider. The effect does not come from a humble verb class.1

父ちちは会社員かいしゃいんです。2
"My father is a company employee."

姉あねは東京とうきょうに住すんでいます。2
"My older sister lives in Tokyo."

The out-group (honorific) forms: お父さん, お母さん, お兄さん, お姉さん​

These are the お- + kinship-noun + -さん forms. Use them to refer to someone else's family member, and also to address your own.14

RelationHonorific (other / address)ReadingRomaji
fatherお父さんおとうさんotōsan4
motherお母さんおかあさんokāsan4
older brotherお兄さんおにいさんoniisan4
older sisterお姉さんおねえさんonēsan4

The pattern is the お- prefix plus the -さん suffix: "mother" becomes okāsan, and "older brother" becomes oniisan.4 The same forms are the standard way to refer to another person's family politely. For parents as a unit, use ご家族・ご両親.42

お母かあさんはお元気げんきですか。2
"Is your mother well?"

お兄にいさんは何歳なんさいですか。2
"How old is your older brother?"

The own / other split has a clean shape that a diagram captures faster than prose:

The override: addressing vs referring​

The asymmetry above is about referring to family when speaking to an outsider. A different rule governs direct address: a younger member addresses an older member with the honorific form, and the older member calls the younger one by name.14

So at home a child says 「お母さん！」(okāsan!) to call to their mother, but tells a teacher 「母は…」(haha wa…).14 Older relatives are not addressed by bare name or by anata / kimi. You address your father as otōsan and your older brother as oniisan.14

Younger siblings invert this. You generally address them by name, not by 弟 / 妹, because the senior member calls the junior by name.4

お父とうさん、ご飯はんだよ。2
"Dad, dinner's ready."

父ちちは今いまいません。2
"My father isn't here right now."

The word for "father" therefore changes depending on whether you are speaking to him or about him:

Why this is uchi-soto, not keigo verbs​

The switch belongs to the in-group / out-group boundary, not to a humble verb conjugation. When speaking to an outsider, the speaker's point of view is shared by the in-group (内, uchi), so in-group referents do not take honorifics. This is why one's own family is referred to with the bare forms.1

The same machinery applies beyond family. Members of one's own company are referred to with plain or humble forms when speaking to an external person, exactly as family members are referred to plainly in front of guests.1

The honorific お…さん forms, then, are not "polite verbs." They are out-group word forms, marked with the お- beautification prefix and -さん.14

The core kinship list​

This is the reference table most learners came for. Every two-word entry follows the own / other rule established above.

Parents and self​

TermReadingRomajiUse
私わたしwatashiI / me2
親おやoyaparent (general)2
父ちちchichimy father (to outsider)2
お父さんおとうさんotōsan(your/their) father; address42
母ははhahamy mother (to outsider)2
お母さんおかあさんokāsan(your/their) mother; address42
両親りょうしんryōshin(my) parents2
ご両親ごりょうしんgo-ryōshin(your/their) parents2

両親りょうしんは大阪おおさかにいます。2
"My parents are in Osaka."

Siblings and generation terms​

Japanese builds seniority into the basic words: 兄 / お兄さん and 姉 / お姉さん mean the older sibling, while 弟 and 妹 mean the younger sibling. There is no neutral "brother" or "sister" word that ignores age.42

The collective nouns are 兄弟きょうだい (kyōdai), "siblings / brothers," and 姉妹しまい (shimai), "sisters."6 兄弟 is commonly used for siblings of mixed gender as well.6

TermReadingRomajiUse
兄あにanimy older brother2
お兄さんおにいさんoniisan(your/their) older brother; address4
姉あねanemy older sister2
お姉さんおねえさんonēsan(your/their) older sister; address4
弟おとうとotōtoyounger brother2
妹いもうとimōtoyounger sister2
兄弟きょうだいkyōdaisiblings (collective)6
姉妹しまいshimaisisters (collective)6

兄弟きょうだいがいますか。2
"Do you have any brothers or sisters?"

妹いもうとは高校生こうこうせいです。2
"My younger sister is a high-school student."

Children and grandchildren​

TermReadingRomajiUse
子 / 子供こ / こどもko / kodomochild2
お子さんおこさんo-ko-san(your/their) child2
息子むすこmusukomy son2
息子さんむすこさんmusuko-san(your/their) son2
娘むすめmusumemy daughter2
娘さん / お嬢さんむすめさん / おじょうさんmusume-san / o-jō-san(your/their) daughter2
孫まごmagomy grandchild2
お孫さんおまごさんo-mago-san(your/their) grandchild2

The other-person reference forms add -さん (息子さん, 娘さん, お子さん, お孫さん); お嬢さん (o-jō-san) is a common polite reference to another's daughter.2

息子むすこは五歳ごさいです。2
"My son is five years old."

お子こさんは何人なんにんですか。2
"How many children do you have?"

Grandparents, uncles, aunts, cousins​

Grandparents have the same own / other split. 祖父そふ (sofu) / 祖母そぼ (sobo) are the own-family reference forms. おじいさん (お祖父さん) / おばあさん (お祖母さん) are the honorific and address forms, and they can also mean "old man / old woman" generically.74

Uncles and aunts read おじ / おば. They are written with one of two kanji pairs that encode seniority: 伯父・伯母 for a parent's elder sibling, and 叔父・叔母 for a parent's younger sibling.89 In speech they are identical. The choice appears only in writing.89 The address and other-person forms are おじさん / おばさん, with -さん.4

いとこ means "cousin." It can be written 従兄弟・従姉妹 with seniority and gender variants, but the kana いとこ covers all of them.

RelationOwn (reference)ReadingOther / addressReading
grandfather祖父そふ (sofu)4おじいさん / お祖父さんおじいさん (ojiisan)7
grandmother祖母そぼ (sobo)4おばあさん / お祖母さんおばあさん (obāsan)4
uncle (elder)伯父おじ (oji)8おじさんおじさん (ojisan)4
uncle (younger)叔父おじ (oji)9おじさんおじさん (ojisan)4
aunt (elder)伯母おば (oba)8おばさんおばさん (obasan)4
aunt (younger)叔母おば (oba)9おばさんおばさん (obasan)4
cousinいとこいとこ (itoko)いとこいとこ (itoko)
One long vowel separates the generations

おじいさん (grandfather, long じい) differs from おじさん (uncle / middle-aged man, short じ) by a single mora. The same contrast appears in おばあさん (grandmother) versus おばさん (aunt / middle-aged woman). Mishear or shorten the vowel, and you have moved a whole generation.47

祖母そぼは今年ことし八十歳はちじっさいです。2
"My grandmother is eighty this year."

お祖父じいさんは元気げんきですか。7
"Is your grandfather well?"

In-law and step terms​

Most N5 lists omit this layer. The core pattern is one prefix; the rest is reference vocabulary above N5.

The 義 (gi-) prefix: 義父, 義母, 義兄, 義弟, 義姉, 義妹​

The prefix 義ぎ (gi) builds in-law, adoptive, and "by-principle" kin terms from the base kinship kanji.10

義父ぎふ (gifu) covers father-in-law (the spouse's father), stepfather, adoptive father, and "father by moral principle." The same pattern yields 義母ぎぼ (gibo), 義兄ぎけい (gikei), 義姉ぎし (gishi), 義弟ぎてい (gitei), and 義妹ぎまい (gimai).10

The 義- forms are largely written and formal. In speech, in-laws are typically addressed and referred to with the ordinary family terms. お義父さん is read おとうさん (otōsan): the 義 is written to mark an in-law on paper, but it is silent in pronunciation. It sounds identical to the word for one's own parent.10

義父ぎふは医者いしゃです。10
"My father-in-law is a doctor."

嫁, 婿, 舅, 姑 and step-relations​

A separate set of single-kanji words names in-laws from the parents' or household perspective. These are above N5 and are given here only as reference.

TermReadingRomajiMeaning
嫁よめyomedaughter-in-law (son's wife); also "bride / wife" colloquially
婿むこmukoson-in-law (daughter's husband); also "bridegroom"
舅しゅうとshūtofather-in-law (spouse's father)
姑しゅうとめshūtomemother-in-law (spouse's mother)

義父・義母 (the 義- set) and 舅・姑 both translate as "parent-in-law." The 義- forms are the neutral modern written terms, while 舅・姑 are older single-kanji words still current in speech and writing. These readings sit above N5 and are included for reference.10

Nuance and usage contexts​

Beyond the table, register and real speech add another layer. Each register below fits a specific social slot.

Register: パパ・ママ, 親父・お袋, and other registers​

パパ / ママ are childish and affectionate address terms for one's own parents. Both are loanwords. おとうちゃん / おかあちゃん sit between childish and casual-affectionate, with the ちゃん diminutive on the otō- / okā- stems.

親父おやじ (oyaji) is an informal, masculine word for one's own father, and by extension "old man" or "boss / shopkeeper." A woman is unlikely to use it for her own father.11 御袋おふくろ (ofukuro) is the affectionate informal counterpart for one's own mother. The spelling relates to 袋 (fukuro, "bag").12

親父 and お袋 stay inside your own family

These words are in-group and casual to rough. They are never used to refer politely to someone else's parents, and 親父 in particular leans toward male speakers. For another person's parents or any formal context, use お父様・お母様 or ご両親.1112

Talking about another person's family politely​

For another person's family, the polite reference set is ご家族 (go-kazoku), ご両親 (go-ryōshin), お父さん, お母さん, お子さん, お孫さん, 息子さん, 娘さん / お嬢さん, plus the spouse terms below.42

For the listener's spouse, use 御主人ごしゅじん (go-shujin) or 旦那だんなさん (danna-san) for the husband, and 奥おくさん (okusan) for the wife.13

ご両親りょうしんによろしくお伝つたえください。2
"Please give my regards to your parents."

Relationship words beyond blood family​

夫おっと (otto) is "my husband," and 妻つま (tsuma) is "my wife." Both are neutral, formal own-side terms used in official documents and plain reference.213

主人しゅじん (shujin) is also "my husband," from an origin meaning "master of the house." The other-person form is ご主人.13 旦那だんな (danna) is a casual "my husband," with the other-person form 旦那さん / 旦那さま.13 奥おくさん (okusan) is "(your/their) wife," while one's own wife is 妻 (tsuma) or the dated 家内 (kanai).2

This own-vs-other split for spouses (妻 versus 奥さん, 夫 / 主人 versus ご主人) mirrors the kinship asymmetry: a plain own-side word and an honorific other-side word.113

Other relationship vocabulary includes 彼かれ (kare, boyfriend / he), 彼女かのじょ (kanojo, girlfriend / she), 恋人こいびと (koibito, sweetheart), パートナー (pātonā, partner), and 友達ともだち (tomodachi, friend).

妻つまは看護師かんごしです。2
"My wife is a nurse."

ご主人しゅじんはお仕事しごとは何なんですか。13
"What does your husband do for work?"

Good to know​

Don't call your own dad お父さん to outsiders​

The single most common beginner error is saying 私のお父さんは医者です to an outsider about one's own father. In-group referents drop the honorific in front of an outsider, so the own-family reference form is plain 父. The honorific お父さん is for someone else's father, or for addressing your own father at home.14

父ちちは医者いしゃです。1
"My father is a doctor."

父 and 母 are plain, not "humble keigo"​

The plain forms are unmarked in-group reference forms, not formal 謙譲語けんじょうご (kenjōgo) verbs. They can feel deferential because the uchi-soto rule strips honorifics from in-group referents, not because the word is a humble-keigo lexeme. Treat 父 as "plain / neutral," not as a "humble verb."1

おじいさん vs おじさん, おばあさん vs おばさん​

If you intend "grandfather" but say おじさんは八十四歳です, you name an uncle instead. The long vowel じい (jī) or ばあ (bā) marks a grandparent. The short じ or ば marks an uncle, aunt, or middle-aged person. One mora separates the generations.47

お祖父じいさんは八十四歳はちじゅうよんさいです。7
"My grandfather is eighty-four years old."

Why older and younger siblings are different words​

Japanese builds seniority directly into the words: 兄 / 弟 and 姉 / 妹 each split a single English word in two, and there is no bare "brother" or "sister" that ignores age. A speaker must know the relative age before they can name the relationship at all. This reflects the seniority-marking that runs through the wider address system.42

The 伯 vs 叔 kanji choice for uncles and aunts​

Both 伯父 / 叔父 read おじ, and both 伯母 / 叔母 read おば. 伯 marks a parent's elder sibling, and 叔 marks a parent's younger sibling. This distinction is inherited from Chinese kin terminology. It is invisible in speech and appears only when writing.89

The 義 in in-law words is written but not spoken​

お義父さん is pronounced exactly like お父さん (otōsan). The 義 is on the page to mark "by marriage," not in the mouth. Read the 義- in-law forms (義父 gifu, 義母 gibo) aloud only in their written or formal context.10

See also​

References​

Footnotes​

  1. Wikipedia contributors. "Honorific speech in Japanese." Wikipedia, the free encyclopedia. https://en.wikipedia.org/wiki/Honorific_speech_in_Japanese. The uchi-soto (内 in-group / 外 out-group) mechanism, the rule that in-group referents (including one's own family) do not take honorifics when speaking to outsiders, and the addressing rule for older relatives (e.g. otōsan in address). Encyclopedic synthesis of the keigo system. ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17

  2. Banno, Eri, et al. Genki I: An Integrated Course in Elementary Japanese. 3rd ed., The Japan Times, 2020. Standard elementary-course treatment of the family vocabulary set, the own-family / other-family two-column split (chichi/otōsan, haha/okāsan, etc.), and the register and particle patterns in the example sentences. (General textbook reference; specific page numbers not pinned in this pass; see Open issues.) ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17 ↩18 ↩19 ↩20 ↩21 ↩22 ↩23 ↩24 ↩25 ↩26 ↩27 ↩28 ↩29 ↩30 ↩31 ↩32 ↩33 ↩34 ↩35 ↩36 ↩37 ↩38 ↩39 ↩40 ↩41 ↩42 ↩43 ↩44 ↩45 ↩46 ↩47 ↩48 ↩49 ↩50 ↩51 ↩52 ↩53 ↩54

  3. Wiktionary contributors. "親戚." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/親戚. Reading しんせき (shinseki) and the "relative(s) / extended kin" sense, listed alongside 家族 (kazoku, immediate family). Wiktionary aggregates Japanese dictionary sources (日本国語大辞典, 大辞林); treated as a tertiary reference. (limitation) ↩

  4. Wikipedia contributors. "Japanese honorifics." Wikipedia, the free encyclopedia. https://en.wikipedia.org/wiki/Japanese_honorifics. The o-…-san pattern on kinship terms (otōsan, okāsan, oniisan, onēsan), the ojisan/ojiisan and obasan/obāsan long-vowel pair, and the household address convention (younger addresses older with an honorific form; older calls younger by name). ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17 ↩18 ↩19 ↩20 ↩21 ↩22 ↩23 ↩24 ↩25 ↩26 ↩27 ↩28 ↩29 ↩30 ↩31 ↩32 ↩33 ↩34

  5. 国際交流基金・日本国際教育支援協会 (Japan Foundation & Japan Educational Exchanges and Services). JLPT Japanese-Language Proficiency Test (official site). https://www.jlpt.jp/e/. JLPT level structure and can-do framework. The JLPT does not publish an official vocabulary list; N5 placement of the core kinship set follows standard N5 curricula consistent with the official can-do statements. ↩

  6. Wiktionary contributors. "兄弟." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/兄弟. Reading きょうだい (kyōdai) and the collective "siblings / brothers (and sisters)" sense. (limitation) ↩ ↩2 ↩3 ↩4

  7. Wiktionary contributors. "おじいさん." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/おじいさん. Grandfather / old man; kanji お祖父さん・お爺さん; the long vowel じい (jī) distinguishing it from おじさん. (limitation) ↩ ↩2 ↩3 ↩4 ↩5 ↩6

  8. Wiktionary contributors. "伯父." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/伯父. Reading おじ (oji, jukujikun) / はくふ (hakufu); sense "uncle older than one's parent," with coordinate term 叔父. (limitation) ↩ ↩2 ↩3 ↩4 ↩5

  9. Wiktionary contributors. "叔父." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/叔父. Reading おじ (oji) / しゅくふ (shukufu); sense "uncle younger than one's parent," coordinate with 伯父. (limitation) ↩ ↩2 ↩3 ↩4 ↩5

  10. Wiktionary contributors. "義父." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/義父. Reading ぎふ (gifu); senses "father-in-law (spouse's father), stepfather, adoptive father, father by moral principle"; the 義 (gi) prefix forming in-law/adoptive terms (義母, 義兄, 義姉). (limitation) ↩ ↩2 ↩3 ↩4 ↩5 ↩6

  11. Wiktionary contributors. "親父." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/親父. Reading おやじ (oyaji); informal sense for one's own father / an old man / a boss; note that the term is masculine in usage. (limitation) ↩ ↩2

  12. Wiktionary contributors. "お袋." Wiktionary, the free dictionary. https://en.wiktionary.org/wiki/お袋. Reading おふくろ (ofukuro); informal sense "one's own mother"; spelling related to 袋 (fukuro, bag), 御袋. (limitation) ↩ ↩2

  13. Unseen Japan (Jay Allen). "Husband or Master? The Debate Over Japanese Words for Husband." unseen-japan.com. https://unseen-japan.com/husband-or-master-the-debate-over-japanese-words-for-husband/. The 夫 (otto) / 主人 (shujin) / 旦那 (danna) set for one's own husband, ご主人・旦那さん for another's, and the "master of the house" origin of 主人 and 旦那. (limitation) ↩ ↩2 ↩3 ↩4 ↩5 ↩6