otona-vs-kodomo

大人 (おとな, otona) and 子ども (こども, kodomo) are two of the most fundamental words in the Japanese language — “adult” and “child.” These nouns show up everywhere: on train fare signs, restaurant menus, event announcements, and in everyday conversation. But beyond simple age labeling, both words carry cultural nuance, and their kanji etymologies are fascinatingly poetic. This guide covers everything you need to know about using these two words naturally in Japanese.

Yuka

Hey Rei, what’s the best way to remember the difference between otona and kodomo?

Rei

The best trick is to associate each word with a strong image or situation. By the end of this article you’ll have one for each — promise!

At a Glance: おとな vs こども

おとな (大人) — Adult and Maturity

おとな means “adult” or “grown-up.” The kanji 大人 literally means “big person” — 大 (big/great) + 人 (person). This is one of the most common irregular kanji readings in Japanese, as you might expect it to read だいじん or おおびと, but it reads おとな. This special reading makes it memorable once you know it.

Figurative meaning: おとな (or おとなっぽい / 大人っぽい) is used to describe mature or sophisticated behavior. Saying 大人な対応 (otonana taiō) means “handling things in a mature/adult manner.” This figurative use appears often in workplaces and in describing someone’s composed reaction to a difficult situation.

Common compounds and expressions:

Example sentence 1:

子どもの頃は早く大人になりたかった。
Kodomo no koro wa hayaku otona ni naritakatta.
When I was a child, I wanted to grow up quickly.

Example sentence 2:

大人料金はおいくらですか？
Otona ryōkin wa o-ikura desu ka?
How much is the adult price/fare?

Example sentence 3:

彼女は年齢より大人っぽく見える。
Kanojo wa nenrei yori otonappoku mieru.
She looks more mature than her age.

Yuka

That makes sense! So otona is about… okay, I think I’m starting to get it.

Rei

You’re getting it! And the more you practice using otona in sentences, the more automatic it becomes. Language learning is all about repetition.

こども (子ども) — Child and Childhood

こども means “child” or “children.” Note: こども is both singular and plural in Japanese — context tells you whether you are talking about one child or many. The kanji 子ども (or 子供) combines 子 (child) + ども/供 (a suffix indicating plurality or a group, though it can also be used for a single child in modern usage).

Kanji note: The government-recommended spelling is 子ども (with hiragana ども) rather than 子供 (all kanji). Both are commonly used, but 子ども is seen more often in official documents and educational materials since 供 (tomo) can carry an older nuance of “servant/follower” that is considered inappropriate when referring to children.

Figurative meaning: こどもっぽい (kodomo-ppoi) or 子どもじみた (kodomo-jimita) describes childish or immature behavior in adults. これは子どもっぽい考えだ (This is a childish way of thinking) is a gentle criticism of immaturity.

Common compounds and expressions:

Example sentence 1:

子どもの頃、毎日公園で遊んでいました。
Kodomo no koro, mainichi kōen de asonde imashita.
When I was a child, I used to play in the park every day.

Example sentence 2:

このレストランは子ども料金がありますか？
Kono resutoran wa kodomo ryōkin ga arimasu ka?
Does this restaurant have a children’s price?

Example sentence 3:

子どもが三人います。
Kodomo ga san-nin imasu.
I have three children.

Yuka

Alright. And now explain kodomo? I want to make sure I have both down.

Rei

Sure! kodomo is actually the easier one to remember once you have a clear mental image. Let’s look at the examples.

Side-by-Side Comparison Table

Common Mistakes English Speakers Make

Mistake 1: Expecting おとな to read as だいじん
大人 is a classic irregular kanji reading (熟字訓, jukujikun). The characters 大 (big) and 人 (person) would logically combine as だいじん or おおびと, but the word is read おとな. This type of irregular reading is common in Japanese for everyday words — memorize it directly rather than trying to derive it from the kanji.

Mistake 2: Not knowing こども is both singular and plural
Japanese nouns have no grammatical plural form. こども can mean “a child” or “children” depending on context. If you need to be specific about plurality, you can add 子どもたち (kodomotachi) — the たち suffix explicitly marks a group. 子どもたちが遊んでいる (The children are playing).

Mistake 3: Confusing 大人気 readings
大人気 can be read two different ways with completely different meanings: おとなげ (otonage) = “adult-like dignity/decorum” (as in 大人げない = unbecoming of an adult); and だいにんき (daininki) = “very popular / hugely popular.” Context determines which reading applies — another reminder that kanji reading requires attention to context.

Decision Flowchart: おとな or こども?

Use this flowchart when describing age or maturity:

Who or what are you describing?
├─ A person who is grown-up / 18 or older → おとな (大人)
│　　├─ On a price sign → 大人料金
│　　├─ Mature behavior → 大人っぽい / 大人な対応
│　　└─ Immature adult behavior → 大人げない
└─ A person who is young / a child → こども (子ども)
　　　├─ On a price sign → 子ども料金
　　　├─ Positive childlike quality → 子どもらしい
　　　├─ Immature/childish behavior → 子どもっぽい
　　　└─ Plural (explicit) → 子どもたち

Quick Quiz

Yuka

Okay Rei, quiz time! I want to test how well I’ve absorbed all this.

Rei

Challenge accepted on your behalf! Let’s see how much of otona and kodomo has sunk in.

Fill in the blank with おとな or こども (in the appropriate form). Answers below.

1. ___になったら、一人暮らしをしたい。(When I become an adult, I want to live alone.)

2. ___の頃は、アニメが大好きでした。(When I was a child, I loved anime.)

3. あの人はいつも___っぽい反応をする。(That person always has a childish reaction.)

4. ___料金と___料金の違いを教えてください。(Please tell me the difference between the adult fare and the children’s fare.)

5. 公園で___たちが走り回っている。(The children are running around in the park.)

Answers:

1. 大人 (otona) — 大人になる: to become an adult.
2. 子ども (kodomo) — 子どもの頃: when I was a child.
3. 子ども (kodomo) — 子どもっぽい: childish/immature reaction.
4. 大人 / 子ども — 大人料金 (adult fare) and 子ども料金 (children’s fare).
5. 子ども (kodomo) — 子どもたち: explicit plural for “the children.”

大人 and 子ども are deceptively simple words that carry cultural depth. From price signs to coming-of-age ceremonies, from childhood nostalgia to maturity expectations, these two words are woven into the fabric of Japanese daily life. Now that you know their kanji, their figurative uses, and their irregular readings, you are ready to use them naturally in any context.

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