Meaning
The kanji 窒 (chitsu) primarily conveys the ideas of "choking," "suffocating," or "stifling." It describes a situation where breathing is obstructed, or the air supply is insufficient, leading to a lack of oxygen. This kanji frequently appears in technical or medical discussions, especially when referring to gases like nitrogen or phenomena related to asphyxiation. As an N1 JLPT kanji, it signifies advanced usage and is often linked to specialized vocabulary, making it essential for comprehending complex Japanese texts.
The character 窒 is a phono-semantic compound, constructed from two radicals. At the top is 穴 (穴かんむり - ana-kanmuri), meaning "hole," "cave," or "cavity." This acts as the semantic component, hinting at enclosure. Below it is 至 (いたる - itaru), meaning "to reach," "to arrive," or "to an extreme," which lends its phonetic element, though its sound has evolved over time. Together, these components visually suggest something reaching (至) into a confined space or hole (穴). This combination creates a sense of blockage or restriction.
Metaphorically, this can be interpreted as airflow reaching a critically confined state where it cannot move freely, resulting in choking or a lack of breath. The "hole" radical strongly emphasizes the enclosure, a key aspect of suffocation. The kanji has 11 strokes. While it's an N1 kanji, it isn't taught in elementary school. Instead, it's considered a jōyō kanji learned at a higher education level or by those aiming for advanced Japanese proficiency.
Readings
On'yomi (音読み) — Chinese-derived readings
The main on'yomi reading for 窒 is チツ. This reading is consistently used in almost all compound words containing this kanji, directly reflecting its origin from Chinese pronunciation. It's a fundamental component in scientific, medical, and industrial terms, often related to gases or the act of suffocating, making it vital for advanced learners.
窒息 (chissoku) — suffocation; asphyxiation. This is likely the most common word using 窒, directly referring to being unable to breathe. You'll often encounter it in emergency situations or medical reports.
彼は煙で窒息しそうになった。 — He nearly suffocated from the smoke.
窒息事故を防ぐために、注意が必要だ。 — Caution is necessary to prevent suffocation accidents.
窒素 (chisso) — nitrogen. This term refers to the chemical element that constitutes a large portion of Earth's atmosphere. Though essential for life, it's not directly breathable by humans in its pure form. It's a foundational term in chemistry and biology.
空気の約80%は窒素である。 — Approximately 80% of the air is nitrogen.
植物は窒素を栄養源とする。 — Plants use nitrogen as a nutrient source.
窒化 (chikka) — nitrification; nitriding. Used in chemistry and material science, this refers to the process of introducing nitrogen into a substance or the chemical conversion of nitrogen compounds. It's a more specialized term.
金属の表面に窒化処理を施す。 — Nitriding treatment is applied to the metal surface.
Kun'yomi (訓読み) — Native Japanese readings
The kanji 窒 has no commonly used kun'yomi (native Japanese readings). It is almost exclusively used in compound words with its on'yomi チツ. This pattern is common for kanji adopted into Japanese primarily as parts of scientific or technical vocabulary, which often came directly from Chinese. Therefore, you won't typically find 窒 used on its own or with hiragana (okurigana) attached to form a native Japanese verb or adjective, unlike many other kanji.
Common Words & Compounds
The kanji 窒 plays a key role in various compound words, primarily in scientific, medical, and environmental discourse. These compounds consistently relate to breathing, gases, and conditions involving the obstruction or restriction of airflow. Grasping these compounds is vital for understanding the nuanced applications of 窒 in advanced Japanese.
Medical and Biological Terms: These compounds directly concern the physiological process of breathing and its cessation. You'll often encounter them in health, safety, and emergency contexts.
窒息 (chissoku) — This is the most direct term for suffocation or asphyxiation, describing when breathing stops due to lack of oxygen.
窒息死 (chissokushi) — Refers specifically to death caused by suffocation, often seen in forensic or medical reports determining the cause of death.
窒息性ガス (chissokusei gasu) — Denotes a type of gas that can cause suffocation by displacing oxygen in the air, such as high concentrations of nitrogen or carbon dioxide.
窒息状態 (chissoku jōtai) — Describes a condition or state of being suffocated or experiencing extreme difficulty in breathing, often used for a victim's condition.
Chemical and Environmental Terms: These terms primarily involve the element nitrogen and its compounds, fundamental to chemistry, agriculture, and environmental science.
窒素 (chisso) — The chemical element nitrogen (N), which forms the largest portion of Earth's atmosphere and is vital for life.
窒化物 (chikkabutsu) — A chemical compound formed between nitrogen and another element, often used in materials science for properties like hardness and heat resistance.
窒素酸化物 (chisso sankabutsu) — A group of compounds known as NOx. These are significant air pollutants contributing to smog, acid rain, and respiratory issues.
窒素循環 (chisso junkan) — The biogeochemical cycle where nitrogen converts into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems, crucial for ecological balance.
窒化処理 (chikka shori) — A heat treatment process that enhances the surface hardness, wear resistance, and fatigue strength of metals by diffusing nitrogen into the material's surface.
Figurative and Broader Contexts:
閉塞窒息 (heisoku chissoku) — This is a specific medical term for obstructive asphyxia, referring to when a physical obstruction prevents air from entering the lungs.
Example Sentences
部屋の換気が悪く、窒息しそうな感覚を覚えた。
Heya no kanki ga waruku, chissoku shi-sō na kankaku o oboeta.
The room's ventilation was poor, and I felt a suffocating sensation.
空気中の窒素は、生物にとって不可欠な元素である。
Kūkichū no chisso wa, seibutsu ni totte fukaketsu na genso de aru.
Nitrogen in the air is an indispensable element for living organisms.
不完全燃焼により、窒息性ガスが発生した。
Fukanzen nenshō ni yori, chissokusei gasu ga hassei shita.
Incomplete combustion produced asphyxiant gas.
子供が小さなものを誤飲して窒息しないよう、注意が必要です。
Kodomo ga chiisana mono o goin shite chissoku shinai yō, chūi ga hitsuyō desu.
Care is needed to prevent children from swallowing small objects and choking.
工場では窒素酸化物の排出量を厳しく規制している。
Kōjō de wa chisso sankabutsu no haishutsuryō o kibishiku kisei shite iru.
The factory strictly regulates the emission of nitrogen oxides.
過度な精神的ストレスは、人を窒息させるかのように感じさせる場合がある。
Kado na seishinteki sutoresu wa, hito o chissoku saseru ka no yō ni kanjisaseru baai ga aru.
Excessive mental stress can sometimes make a person feel as if they are suffocating.
事故現場では、多数の窒息死が確認された。
Jiko genba de wa, tasū no chissokushi ga kakunin sareta.
At the accident scene, numerous deaths by suffocation were confirmed.
農業における窒素循環の理解は、土壌の健康にとって重要です。
Nōgyō ni okeru chisso junkan no rikai wa, dojō no kenkō ni totte jūyō desu.
Understanding the nitrogen cycle in agriculture is important for soil health.
金属の耐久性を高めるために、窒化処理が施されることがある。
Kinzoku no taikyūsei o takameru tame ni, chikka shori ga hodokosareru koto ga aru.
Nitriding treatment may be applied to metal to enhance its durability.
Memory Tip
To remember 窒, picture its components: 穴 (hole or confined space) on top and 至 (to reach or arrive) below. Imagine someone in a tiny, enclosed "hole" or space, desperately trying to breathe. The air supply is so restricted that they "reach" a critical point of suffocation. The "hole" radical emphasizes this enclosure and lack of open space, while "至" conveys the sense of arriving at an extreme or dire state. For example, think of someone trapped, reaching a dead end in a narrow, unventilated tunnel. This scenario vividly illustrates the severe lack of air and the feeling of choking. This strong visual link between a confined space and a breathing crisis helps firmly connect 窒 with the meanings of "suffocate," "choke," or "stifle."