Meaning
姻 means marriage and matrimony—specifically the formal bonds formed between families when two people wed. You won't hear it in casual conversation. Instead, you'll find it in legal documents, family law, civil registration offices, and formal ceremonies. Its most important compound is 婚姻, the standard legal term for marriage in Japanese—the word printed on the form you hand to the municipal office when you get married.
Structurally, 姻 has two parts. The left side is the radical 女 (おんな), meaning woman. The right side is 因 (いん), meaning cause, reason, or foundation. Both halves contribute: 女 places 姻 within the semantic field of femininity, family, and social bonds; 因 adds the idea of marriage as the foundational event that binds two people—and two families—into new legal and social relationships. 因 also supplies the pronunciation: イン.
Stroke count: 9 total—3 from 女, 6 from 因. 姻 is a Joyo kanji (常用漢字) with no assigned elementary school grade, placing it in the secondary-education or adult-literacy category. JLPT level: N1.
The 女 radical appears across a cluster of related kanji: 嫁 (bride, daughter-in-law), 婚 (wedding ceremony), 娘 (daughter), 姉 (older sister). Spotting 女 on the left immediately signals that the kanji belongs to this family of women, kinship, and social bonds.
Readings
On'yomi (音読み) — Chinese-derived readings
姻 has one on'yomi reading: イン. It comes from classical Chinese and matches the phonetic component 因, also read イン in Japanese. The pattern is reliable—when 因 appears as a component inside a kanji, イン is almost always the reading.
イン never appears alone; it only shows up inside compound words (熟語, じゅくご). Learning 姻 means learning its compounds and knowing which register they belong to.
Key compounds with the イン reading:
- 婚姻 (kon'in) — marriage, matrimony; the primary formal and legal term for marriage in Japanese
- 姻族 (inzoku) — relatives by marriage, in-laws as a legally defined family category
- 姻戚 (inseki) — relatives by marriage; slightly more literary than 姻族
- 姻縁 (in'en) — matrimonial bond or tie; often carries a sense of fate or destiny
Kun'yomi (訓読み) — Native Japanese readings
姻 has no kun'yomi readings. This is common among kanji that entered Japanese through classical Chinese literary and administrative texts. Marriage as a formal institution came packaged in Chinese-derived vocabulary, so 姻 was absorbed as a pure on'yomi character—no native Japanese reading was ever attached.
For study purposes, that simplifies things: concentrate on 婚姻 and its register. Get that one compound right, and you're ready for any N1-level encounter with this kanji.
Common Words & Compounds
姻 appears almost exclusively in formal and legal vocabulary. Key compounds by theme:
Marriage and Legal Terms
- 婚姻 (kon'in) — marriage, matrimony; the formal legal term in official documents and civil registration
- 婚姻届 (kon'in todoke) — marriage registration form; submitted to the municipal office to make a marriage legally valid
- 婚姻届出 (kon'in todokede) — the act of filing the marriage registration
- 婚姻法 (kon'in hō) — marriage law; the legal framework governing the institution of marriage
- 婚姻率 (kon'in ritsu) — marriage rate; a statistical measure of how frequently marriage occurs in a population
- 婚姻関係 (kon'in kankei) — marital relationship; the legal status of being married
- 婚姻成立 (kon'in seiritsu) — establishment of marriage; the legal moment at which a marriage becomes valid
Family and Kinship Terms
- 姻族 (inzoku) — relatives by marriage; a legal category in Japanese family law covering in-laws and their kin
- 姻戚 (inseki) — in-laws, relatives through marriage; used in both legal and literary contexts
- 姻縁 (in'en) — the bond formed by marriage; often implies fate or a destined connection
Example Sentences
婚姻は書類一枚で法的に成立する。
Kon'in wa shorui ichimai de hōteki ni seiritsu suru.
A marriage becomes legally valid with a single form.
婚姻届を市役所に提出した。
Kon'in todoke wo shiyakusho ni teishutsu shita.
We submitted the marriage registration form to the city hall.
二人は婚姻関係にある。
Futari wa kon'in kankei ni aru.
The two are in a marital relationship.
彼女の姻族は大家族だ。
Kanojo no inzoku wa daikazoku da.
Her relatives by marriage form a large family.
この国の婚姻率は年々低下している。
Kono kuni no kon'in ritsu wa nennen teika shite iru.
The marriage rate in this country is declining year by year.
日本の婚姻法は戦後に大幅に改正された。
Nihon no kon'in hō wa sengo ni ōhaba ni kaisei sareta.
Japan's marriage law was substantially revised after the war.
二人の姻縁は、遠い国での出会いから始まった。
Futari no in'en wa, tōi kuni de no deai kara hajimatta.
Their matrimonial bond began with a chance meeting in a distant land.
婚姻関係の解消には法的な手続きが必要だ。
Kon'in kankei no kaishō ni wa hōteki na tetsuzuki ga hitsuyō da.
Dissolving a marital relationship requires legal procedures.
姻戚の支援が彼のキャリアを大きく助けた。
Inseki no shien ga kare no kyaria wo ōkiku tasuketa.
Support from his relatives by marriage greatly helped his career.
彼女は婚姻届を出す前に、両親に相談した。
Kanojo wa kon'in todoke wo dasu mae ni, ryōshin ni sōdan shita.
Before submitting the marriage registration form, she consulted her parents.
Memory Tip
Break 姻 into its two halves: 女 (woman) on the left, 因 (cause) on the right. Picture the moment a woman steps forward to be married—that act becomes the cause that joins two families permanently. The structure mirrors the meaning: marriage is, literally and visually, a woman at the center of a binding cause.
The component 因 also pins down the pronunciation: イン. It reads the same way in the standalone character 因, making it a reliable phonetic anchor across multiple kanji.
Vietnamese speakers get a direct shortcut: 婚姻 maps straight onto hôn nhân (hôn = 婚, nhân = 姻). Know one, and the other comes free.