熱 — Heat, Fever, Passion

Meaning

The kanji 熱ねつ primarily conveys the concept of heat. Its meaning extends to include fever, passion, and enthusiasm. This versatile character appears in various contexts, from describing an object's temperature to expressing fervent human emotion.

Its origin is a phono-semantic compound. The upper part, 埶, serves as both a phonetic component and an ideographic hint, originally depicting a person planting a seedling. This suggests the act of 'arranging' or 'handling' something. The lower component, 灬, is the 'fire' radical (火), which appears as four dots when positioned at the bottom of a character. This radical clearly signifies fire, burning, or intense energy, directly linking to the core meaning of heat.

The visual combination logically connects the idea of something being handled or affected by fire, leading to heat. Over time, its meaning evolved. It shifted from the literal heat generated by burning objects to the physiological heat of a fever. Furthermore, it came to represent the metaphorical 'heat' of strong emotions like passion or zeal. This kanji has 15 strokes and is taught in the 4th grade in Japanese elementary schools, although its JLPT relevance begins at N3.

Readings

On'yomi (音読み) — Chinese-derived readings

The primary On'yomi reading for 熱ねつ is ネツ (netsu). This reading is most commonly used when the kanji appears as part of a compound word. Such words often denote abstract concepts of heat, fever, or strong feelings. It carries a more formal or clinical nuance compared to its Kun'yomi counterpart.

発熱はつねつ (hatsunetsu) — fever, generation of heat. Example: 発熱はつねつは病気びょうきの兆候ちょうこうです。

(Hatsunetsu wa byōki no chōkō desu. - Fever is a symptom of illness.)

熱心ねっしん (nesshin) — enthusiasm, zeal. Example: 彼かれは仕事しごとに熱心ねっしんです。

(Kare wa shigoto ni nesshin desu. - He is enthusiastic about his work.)

情熱じょうねつ (jōnetsu) — passion, enthusiasm, zeal. Example: 彼女かのじょは仕事しごとに情熱じょうねつを持もっています。

(Kanojo wa shigoto ni jōnetsu o motte imasu. - She has passion for her work.)

Kun'yomi (訓読み) — Native Japanese readings

The main Kun'yomi reading for 熱ねつ is あつ.い (atsu.i). When read as あつい, it typically functions as an adjective to describe something physically hot to the touch. It is crucial to distinguish this from 暑あつい, which also reads as あつい but specifically refers to hot weather. 熱あつい primarily describes the temperature of an object or liquid.

熱あついお茶ちゃ (atsui ocha) — hot tea. Example: 熱あついお茶ちゃを飲のむ。

(Atsui ocha o nomu. - I drink hot tea.)

熱あついコーヒー (atsui kōhī) — hot coffee. Example: 朝あさは熱あついコーヒーを飲のみます。

(Asa wa atsui kōhī o nomimasu. - I drink hot coffee in the morning.)

熱あつい風呂ふろ (atsui furo) — hot bath. Example: 熱あつい風呂ふろに入はいりたい。

(Atsui furo ni hairitai. - I want to take a hot bath.)

Common Words & Compounds

The kanji 熱ねつ forms many common words and compounds, showcasing its diverse applications. These are grouped by theme for clarity.

Health & Temperature

発熱はつねつ (hatsunetsu) — fever.
高熱こうねつ (kōnetsu) — high fever.
微熱びねつ (binetsu) — slight fever.
熱中症ねっちゅうしょう (necchūshō) — heatstroke.
体温たいおん (taion) — body temperature.

Emotion & Passion

熱心ねっしん (nesshin) — enthusiasm, zeal, eager.
情熱じょうねつ (jōnetsu) — passion, ardor.
熱意ねつい (netsui) — ardor, zeal, eagerness.
熱狂ねっきょう (nekkyō) — frenzy, wild enthusiasm.
熱血ねっけつ (nekkesu) — hot-blooded, passionate.

Other General Compounds

加熱かねつ (kanetsu) — heating, to heat up.
耐熱たいねつ (tainetsu) — heat-resistant.
熱帯ねったい (nettai) — tropics.
熱戦ねっせん (nessen) — fierce battle, close contest.
加熱式かねつしき (kanetsushiki) — heating type (e.g., heated tobacco).
温熱おんねつ (onnetsu) — warmth, heat.

Example Sentences

お湯ゆが熱あつすぎて、入はいれません。

Oyu ga atsusugite, hairemasen.

The water is too hot; I can't get in.

子供こどもが急きゅうに熱ねつを出だしました。

Kodomo ga kyū ni netsu o dashimashita.

My child suddenly developed a fever.

彼かれは仕事しごとにとても熱心ねっしんだ。

Kare wa shigoto ni totemo nesshin da.

He is very enthusiastic about his work.

熱ねつがあるから、今日きょうは学校がっこうを休やすむことにした。

Netsu ga aru kara, kyō wa gakkō o yasumu koto ni shita.

I have a fever, so I decided to take the day off from school today.

彼女かのじょは夢ゆめに情熱じょうねつを傾かたむけている。

Kanojo wa yume ni jōnetsu o katamukete iru.

She pours her passion into her dream.

熱湯ねっとうを使つかってラーメンを作つくります。

Nettō o tsukatte rāmen o tsukurimasu.

I will make ramen using boiling water.

彼かれの熱意ねついが周まわりの人ひと々を動うごかした。

Kare no netsui ga mawari no hitobito o ugokashita.

His enthusiasm inspired the people around him.

熱あつい食たべ物ものは冷さましてから食たべてください。

Atsui tabemono wa samashite kara tabete kudasai.

Please cool down hot food before eating it.

試合しあいは熱戦ねっせんの末すえ、引ひき分わけになった。

Shiai wa nessen no sue, hikiwake ni natta.

The match ended in a draw after a fierce battle.

Memory Tip

Visualize the kanji 熱ねつ as a vivid scene. The upper part, 埶, resembles a person (found at the bottom right of 埶) carefully planting or handling an item (the left side of 埶) with a tool. This item is then placed over fire (灬, the four dots at the bottom), causing it to become hot. Perhaps this individual is passionately preparing a hot meal or striving to heat an object with great zeal. The fire below symbolizes the origin of all heat, fever, and passion. So, remember it as: 'A passionate person handles things over fire, generating heat.'