Meaning
温 means warmth — the comfortable, gentle kind. Not scorching heat, but the pleasant feeling of warm soup on a cold morning, a mild spring afternoon, or a kind and unhurried personality. In everyday Japanese, 温 appears in weather forecasts, medical checkups, and descriptions of someone's character alike.
The structure tells the story. On the left is 氵, the water radical (three dots). On the right is 昷, a component suggesting a container holding something inside. Together: warm water held in a vessel — a bath, a hot spring, a ceramic cup of tea. That image is enough to make the meaning stick.
Japanese children learn 温 in Grade 3, around age 8–9. It has 12 strokes and appears throughout both everyday speech and formal writing. For Vietnamese learners, the Hán-Việt reading ÔN is a useful anchor. It shows up in ôn hòa (gentle, moderate) and ôn tập (to review — literally re-warming knowledge). The connection to Japanese is direct.
Readings
On'yomi (音読み) — Chinese-derived readings
On'yomi: オン. This reading appears in compound words (熟語, jukugo) and dominates formal, scientific, and technical contexts — temperature measurements, climate terms, medical language. If 温 is sitting next to another kanji, it is almost certainly read オン.
- 温度 (ondo) — temperature (the standard word for degree of heat; weather, water, body)
- 体温 (taion) — body temperature (what a thermometer reads; used in medical contexts)
- 気温 (kion) — air temperature (heard in every weather forecast)
- 高温 (kouon) — high temperature (cooking, industry, heatwaves)
- 低温 (teion) — low temperature (food storage, cold science)
- 温泉 (onsen) — hot spring
- 温暖 (ondan) — mild, warm (climate descriptor)
- 温室 (onshitsu) — greenhouse (lit. "warm room")
Kun'yomi (訓読み) — Native Japanese readings
All kun'yomi forms share the base あたた. Use these when 温 appears alone or with hiragana endings (okurigana), rather than inside a kanji compound.
- 温か (atataka) — warm (noun/adjective stem)
- 温かい (atatakai) — warm, cozy (い-adjective; describes warm food, a warm hand)
- 温まる (atatamaru) — to warm up, to become warm (intransitive verb; the subject warms itself)
- 温める (atatameru) — to warm something up (transitive verb; you heat an object — food, a drink, a room)
One distinction worth learning now: 温かい and 暖かい share the same reading (atatakai) but differ in usage. 温かい describes warmth you feel directly — warm soup, a warm hand. 暖かい describes ambient warmth — warm weather, a warm room. Both appear at N3 level.
Common Words & Compounds
温 spans many domains of daily Japanese. Here are key compounds by category.
Temperature & Science
- 温度 (ondo) — temperature
- 体温 (taion) — body temperature
- 気温 (kion) — air temperature
- 高温 (kouon) — high temperature
- 低温 (teion) — low temperature
- 常温 (jouon) — room temperature, ambient temperature
Nature & Environment
- 温泉 (onsen) — hot spring
- 温暖 (ondan) — warm, mild (climate)
- 温暖化 (ondanka) — global warming (lit. "becoming warm")
- 温帯 (ontai) — temperate zone (the band between tropics and polar regions)
Daily Life & Character
- 温室 (onshitsu) — greenhouse (plants grown in controlled warmth)
- 温和 (onwa) — gentle, easygoing (describes personality, not temperature)
- 温かい心 (atatakai kokoro) — a warm heart, kindness
- 温める (atatameru) — to heat up food or a drink
Example Sentences
今日の気温は25度で、とても温かいです。
Kyou no kion wa nijuugo-do de, totemo atatakai desu.
Today's air temperature is 25 degrees — it's very warm.
体温を測ったら、37度でした。
Taion wo hakattara, sanjuushichi-do deshita.
When I took my temperature, it was 37 degrees.
温泉に入ると、体が温まります。
Onsen ni hairu to, karada ga atatamarimasu.
When you get into a hot spring, your body warms up.
冷めたコーヒーを電子レンジで温めました。
Sameta koohii wo denshi renji de atatamemashita.
I warmed up the cold coffee in the microwave.
温暖化は地球にとって深刻な問題です。
Ondanka wa chikyuu ni totte shinkoku na mondai desu.
Global warming is a serious problem for the Earth.
温室の中で野菜を育てています。
Onshitsu no naka de yasai wo sodatete imasu.
We grow vegetables inside the greenhouse.
彼女は温和な性格で、誰にでも優しいです。
Kanojo wa onwa na seikaku de, dare ni demo yasashii desu.
She has a gentle personality and is kind to everyone.
常温で保存できる食品もあります。
Jouon de hozon dekiru shokuhin mo arimasu.
There are also foods that can be stored at room temperature.
春になって、気候が温暖になってきました。
Haru ni natte, kikou ga ondan ni natte kimashita.
Spring arrived, and the weather has turned mild and warm.
温かいスープは寒い日にぴったりです。
Atatakai suupu wa samui hi ni pittari desu.
Warm soup is perfect for a cold day.
Memory Tip
Picture a warm bath. The left side of 温 is 氵 — three water drops. The right side suggests a container holding something inside. Water in a warm vessel: exactly like a Japanese お風呂 (ofuro, bathtub) or an 温泉 (onsen). That image alone is enough to lock in the meaning. For Vietnamese learners, tie it to ÔN HÒA — a calm, moderate personality, warm like the feeling the kanji describes.