Meaning
The N1 kanji 膜 primarily means "membrane," "film," "layer," or "covering." It refers to a thin, pliable layer that typically covers, separates, or lines a surface or structure, whether biological, chemical, or even metaphorical. This kanji frequently appears in scientific and medical terminology, used in various contexts from the human body's intricate systems to industrial materials. Across these applications, its meaning consistently denotes a delicate, often transparent or translucent, protective or functional layer.
The character 膜 is a phono-semantic compound, combining both a semantic and a phonetic component. The left-hand radical, 月 (also known as 肉月 or "meat-moon"), acts as the semantic indicator. When 月 appears on the left side of a kanji and relates to the body or flesh, it is actually a variant of 肉 (meat/flesh). This clearly signals that the kanji's meaning is related to anatomical structures or biological tissues. This link is significant, as membranes are fundamental components of living organisms, from cell membranes to eardrums. The right-hand component, 莫, serves as the phonetic element, providing the "maku" or "boku" sound. Interestingly, it also carries a subtle semantic hint of "not" or "none," which could allude to the thin, almost intangible nature of a membrane. However, its main role here is phonetic. This visual structure directly communicates that 膜 refers to a "fleshy" or "body-related" layer. Composed of 14 strokes, 膜 is not typically taught in the standard elementary school curriculum. Its N1 JLPT level aligns with its status as an advanced Jōyō kanji, frequently appearing in higher-grade materials.
Readings
On'yomi (音読み) — Chinese-derived readings
On'yomi readings are derived from the Chinese pronunciation of a character and are typically used when the kanji forms part of a compound word. For 膜, the primary On'yomi is マク.
マク (maku): This is the most common and primary On'yomi for 膜, used in almost all modern compounds. It directly translates to "membrane" or "film." Its widespread use highlights the kanji's frequent appearance in scientific, medical, and technical contexts where precision is crucial.
細胞膜 (saibōmaku) — cell membrane
薄膜 (hakumaku) — thin film
鼓膜 (komaku) — eardrum (tympanic membrane)
ボク (boku): This reading is significantly less common than マク and is primarily encountered in older, highly specialized, or sometimes archaic terminology. While technically an On'yomi, its usage is extremely rare in modern Japanese, even in most technical fields. Learners will almost certainly not encounter it. For all practical purposes, focusing solely on マク is sufficient, as there are virtually no common compounds that use ボク.
Kun'yomi (訓読み) — Native Japanese readings
The kanji 膜 does not have any commonly recognized or regularly used Kun'yomi readings. Kun'yomi are native Japanese words assigned to a kanji, often conveying a concept that existed in Japanese before the kanji's introduction. However, the concept of "membrane" or "film," as precisely conveyed by 膜, was predominantly adopted through Chinese influence. Consequently, this kanji is almost exclusively used with its On'yomi readings. This pattern is common for kanji that represent highly specific, often technical or abstract concepts introduced from China. Therefore, you will almost exclusively encounter 膜 within compound words using its On'yomi.
Common Words & Compounds
The kanji 膜 appears in a wide array of specialized terms, particularly in biology, medicine, chemistry, and physics. This usage underscores its core meaning of a thin, dividing, or protective layer.
Biological & Medical Terminology
- 細胞膜 (saibōmaku) — cell membrane
- 鼓膜 (komaku) — eardrum, tympanic membrane
- 網膜 (mōmaku) — retina
- 粘膜 (nenmaku) — mucous membrane
- 脳膜 (nōmaku) — meninges (membranes covering the brain)
- 漿膜 (shōmaku) — serous membrane
Scientific & Technical Terminology
- 薄膜 (hakumaku) — thin film (e.g., in optics or materials science)
- 皮膜 (himaku) — coating, film (e.g., protective film, oxide film)
- 高分子膜 (kōbunshimaku) — polymer membrane
- 半透膜 (hantōmaku) — semi-permeable membrane
- 有機膜 (yūkimaku) — organic membrane
General & Figurative Usage
While mostly technical, 膜 can also appear in more general or even figurative contexts, often maintaining its sense of a thin, covering layer.
- 膜張る (makuharu) — to form a film/scum (e.g., on liquid surface)
- 透明な膜 (tōmei na maku) — transparent film/membrane
Example Sentences
この微生物は強固な細胞膜を持っています。
Kono biseibutsu wa kyōko na saibōmaku o motteimasu.
This microorganism has a strong cell membrane.
耳の中にある鼓膜は音を振動させて伝えます。
Mimi no naka ni aru komaku wa oto o shindō sasete tsutaemasu.
The eardrum inside the ear vibrates to transmit sound.
カメラレンズには反射防止の薄膜が施されています。
Kamera renzu ni wa hansha bōshi no hakumaku ga hodokosareteimasu.
Camera lenses are coated with an anti-reflective thin film.
目の奥にある網膜は光を感知する重要な膜です。
Me no oku ni aru mōmaku wa hikari o kanchi suru jūyō na maku desu.
The retina at the back of the eye is an important membrane that detects light.
新鮮な牛乳の表面には、薄い膜が張ることがあります。
Shinsen na gyūnyū no hyōmen ni wa, usui maku ga haru koto ga arimasu.
A thin film can sometimes form on the surface of fresh milk.
胃の内側は粘膜で覆われており、酸から保護されています。
I no uchigawa wa nenmaku de oowareteori, san kara hogosareteimasu.
The inside of the stomach is covered with a mucous membrane and protected from acid.
この最新の分離システムには高性能な高分子膜が使用されています。
Kono saishin no bunri shisutemu ni wa kōseinō na kōbunshimaku ga shiyō sareteimasu.
This latest separation system employs a high-performance polymer membrane.
脳と脊髄を包む三層の膜を脳膜と呼びます。
Nō to sekizui o tsutsumu sansō no maku o nōmaku to yobimasu.
The three layers of membranes surrounding the brain and spinal cord are known as the meninges.
この素材は水は通さず空気だけを通す半透膜でできています。
Kono sozai wa mizu wa tōsasazu kūki dake o tōsu hantōmaku de dekiteimasu.
This material is a semi-permeable membrane that allows only air, not water, to pass through.
Memory Tip
To remember the kanji 膜, meaning "membrane" or "film," focus on its two main components. The left side, 月, is the "meat" or "flesh" radical (肉月) when it appears on the left, indicating something related to the body or organic tissue. Think of it as a slice of meat or part of a living organism. The right side is 莫, which by itself can mean "not" or "none," but here primarily acts as a phonetic component for "maku." However, you can associate 莫 with "sparse" or "vague," suggesting something thin and almost invisible. So, you can imagine a "thin, almost invisible layer (莫) of flesh/body (月)," which aptly describes a membrane. Picture a delicate, thin membrane covering a piece of meat or a transparent film on a biological structure, highlighting its thin, biological nature.