Meaning of Onii-chan, Onee-chan, Onii-san and Onee-san

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Have you ever wondered what it means onii-chan, onee-chan, onii-san, onee-san and other Japanese variations? These words are used to refer to brothers in the Japanese language and are often heard in anime. In this article, we will do a thorough search to understand the meaning and difference of these words.

We have previously written an article talking about the Japanese family members, to remember let's also leave a video that our Sensei made about family members below.

Before you start reading this in-depth research and explanation of the different ways to say brother or sister in Japanese, we recommend watching our video about family members in Japanese.


The meaning of Onii-chan, Onee-chan, Onii-san, Onee-san

Onii-chan and Onee-chan it is nothing more than an informal way of speaking older brother and older sister. Onii [お兄] literally means big brother and Onee [お姉] means big sister. The chan she is an honorary of child treatment, informed and intimate, as if she were a diminutive (little sister).

The most formal and common is to use the suffix san, so we also listen a lot to the words onii-san for older brother and onee-san for older sister. Both of these expressions oniichan, oneechan, oniisan and oneesan can be used as an honorary suffix after the name such as: Kevin-oniichan.


Do you happen to like younger sisters? I hope you are none Lolicon if I'm not going to kill you! The younger sisters are all mine!

O significado de onii-chan, onee-chan e semelhantes
Foto do anime – Ore no Imouto ga Konnani kawaii wake ga nai

This treatment is used for any older sibling you have, sometimes it is even used with people you consider a sibling, even if you are not related.


Younger brothers have word-like treatments otouto [弟] which means little brother and imouto [妹] which means little sister. These words don't usually use a suffix.

See a complete basic table with the different ways of saying brothers and sisters in Japanese:

兄弟きょうだいkyoudaiBrothers Sisters
あにaniOlder brother
あねaneEldest sister
おとうとotoutoYounger brother
いもうとimoutoYounger sister
双子ふたごfutagoTwins, twins
義弟ぎていgiteiYounger half brother
義妹ぎまいgimaiYounger stepsister

Oniichan or Onii-chan, which one is right?

There is no correct way, this feature is just a romanization option that we use to separate the words brother from the suffix chan or another suffix like san. Be careful not to just write onichan because then you will be referring to the demon, ogre or monster Oni [鬼].

O significado de onii-chan, onee-chan e semelhantes

Futago - When are twin brothers?

If both are twin brothers, what do they call each other? Who will decide to be the younger brother or older brother? The Japanese word for twins is futago [双子] which literally means children in pairs or together.

In reality, everyone is already aware that even twins, even when born at the same time, are taken in an order, so those who first came out of the mother's belly are considered older. So it can be said:

  • futago no ani [双子の兄] twin brother;
  • futago no ane [双子の姉] twin sister;
  • futago no oniisan [双子のお兄さん] older twin brother;
  • futago on oneesan [双子のお姉さん] older twin sister;
  • futago in otouto [双子の弟] younger twin brother;
  • futago no imouto [双子の妹] younger twin sister;
  • tsuin [ツイン] from English twins;

Remember if! Never learn Japanese by studying isolated words. If you are confused about the correct order or way to study the Japanese language. We recommend reading our Study Guide for Learning Japanese.

Significado de onii-chan, onee-chan, onii-san e onee-san
Duas irmãs abraçando um Pokemon

The different ways to speak older brother in Japanese

In Japanese there is a hierarchy of treatment, a formal, common and informal language. This is one of the main reasons why there are so many variations and ways to say big brother in Japanese. To make it easier, let's put a list of words below, exemplifying the idea a little:

Remembering that all the words in the list below refer to older sisters or brothers: 

descriptionOlder brotherElder sister
Keigo - Too formal - Sovereignonii-sama [お兄さま]onee-sama [お姉さま]
Sonkeigo (brothers from above)aniue [兄上]aneue [姉上]
Formal - Daily life - Commononii-san [お兄さん]onee-san [お姉さん]
A little more informalnii-san [兄さん]nee-san [姉さん]
Without any respectful, informal suffixnii [兄]nee [姉]
Informal and diminutive suffixonii-chan [お兄ちゃん]onee-chan [お姉ちゃん]
Totally informal with diminutive suffixnii-chan [兄ちゃん]nee-chan [姉ちゃん]
Alternative to nii and neeani [兄]ane [姉]
Precious, esteemed, honorableAniki [兄貴]aneki [姉貴]
Significado de onii-chan, onee-chan, onii-san e onee-san

Aniki it is often used by the yakuza, it is like a comrade brother, where the character [貴] refers to something precious, esteemed and valuable.

Kyoudai and Shimai - Other ways to talk about siblings

The relationship between younger and older siblings is highly valued in Japan, not to mention that the Japanese have a knack for placing younger sisters who call their brother onii-chan in anime.

We already mentioned that brother and little sister are imouto [妹] and otouto [弟], but remember that it is not as common to use suffixes as san [さん] and chan [ちゃん] for younger siblings, but neither is it wrong or unusual.

If you search for younger sister at the jisho you will see that there are infinite ways to convey the idea of a younger sister, however unusual.

Significado de onii-chan, onee-chan, onii-san e onee-san
Foto do anime Uchuu Kyoudai – Irmãos no Espaço

If we want to speak in the plural brothers and sisters we can use the combination of the ideograms of older brother with younger brother. Speaking in Japanese kyoudai [兄弟] and sisters in Japanese are spelled shimai [姉妹].

Kyoudai can encompass all siblings even female, although you can rarely find Kyoudai written in other ways using 2 of the 4 characters used for siblings [兄 - 弟 - 姉 - 妹].


Have you noticed how anime overdo this little sister scheme? Most of the time they are lolis, but do you know what loli means? Click here and read our article on loli, lolicon and lolita.

I hope this article has cleared all doubts about the words onii-chan, onee-chan, onii-san and onee-san, others related to brothers in Japanese like imouto, otouto, kyoudai and shimai! Thanks for the comments and shares!

Significado de onii-chan, onee-chan, onii-san e onee-san - banner desenhar