Meaning
The kanji 細 covers the meanings of thin, slender, fine, narrow, and detailed. It describes both physical thinness — a narrow alleyway, a slender wrist, a fine thread — and abstract precision, such as careful attention to detail.
The character breaks into two parts. The left side is 糸 (ito), the radical for thread or silk. The right side, 囟, historically depicted the fontanelle — the soft spot on a newborn's skull — suggesting something small and delicate. Together, they form the image of a single fine thread: thin, fragile, and demanding careful handling. That one image carries all the kanji's meanings.
細 is a Grade 2 kanji — Japanese children encounter it around age 7 or 8. It has 11 strokes and belongs to the 糸 (thread) radical family, alongside characters related to fiber and fabric. At N3, both senses are expected: the physical (thin/slender) and the abstract (detailed/minute).
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi is サイ (sai), used almost exclusively in compound words. It leans toward the abstract — fine, minute, detailed — rather than simple physical thinness. Spot 細 in a two-kanji compound and サイ is nearly always the reading.
- 細心 (saishin) — meticulous, careful, scrupulous
- 細菌 (saikin) — bacteria, germs (literally "minute organism")
- 細部 (saibu) — details, fine points
- 細胞 (saibou) — cell (biology)
- 詳細 (shousai) — details, particulars, specifics
- 明細 (meisai) — itemized details, breakdown
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi readings are ほそ・い (hosoi), ほそ・る (hosoru), こま・か (komaka), and こま・かい (komakai). Each carries its own nuance.
ほそい (hosoi) means physically thin or slender — a narrow road, a slender finger, a quiet voice. ほそる (hosoru) is the verb: to grow thin, to slim down. こまかい (komakai) shifts toward detail and precision — fine sand, tiny print, or someone who watches every yen.
- 細い道 (hosoi michi) — a narrow path, a thin road
- 細る (hosoru) — to become thin, to grow slender
- 細かい字 (komakai ji) — fine print, tiny characters
- 細かい話 (komakai hanashi) — a detailed story, a minute account
Common Words & Compounds
細 turns up across many areas — body descriptions, science, craftsmanship, and everyday conversation.
Physical thinness / Shape:
- 細い (hosoi) — thin, slender, narrow
- 細長い (hosonagai) — long and thin, elongated
- 細め (hosome) — rather thin, on the thin side
- 細道 (hosomichi) — narrow path, alleyway
Detail / Precision:
- 細かい (komakai) — fine, detailed, minute, fussy
- 細心 (saishin) — meticulous care, scrupulousness
- 詳細 (shousai) — full details, particulars
- 細部 (saibu) — details, fine points
- 明細 (meisai) — itemized statement, breakdown
Science / Technical:
- 細菌 (saikin) — bacteria, microbe
- 細胞 (saibou) — biological cell
- 繊細 (sensai) — delicate, sensitive, subtle
Craftsmanship / Work:
- 細工 (saiku) — handiwork, craftsmanship, fine work
- 細かく (komakaku) — in detail, minutely (adverb)
Example Sentences
彼女は細い指でピアノを弾いている。
Kanojo wa hosoi yubi de piano wo hiite iru.
She is playing the piano with slender fingers.
この道は細くて車が通れない。
Kono michi wa hosokute kuruma ga toorenai.
This road is so narrow that cars cannot pass through.
細かいことを気にしないでください。
Komakai koto wo ki ni shinaide kudasai.
Please don't worry about the small details.
先生は細心の注意を払って採点した。
Sensei wa saishin no chuui wo haratte saiten shita.
The teacher graded the papers with meticulous attention.
詳細については、後ほどご連絡します。
Shousai ni tsuite wa, nochihodo go-renraku shimasu.
Regarding the details, we will contact you later.
彼は繊細な性格で、すぐ傷つく。
Kare wa sensai na seikaku de, sugu kizutsuku.
He has a sensitive personality and gets hurt easily.
明細書を確認したら、間違いがあった。
Meisaisho wo kakunin shitara, machigai ga atta.
When I checked the itemized statement, there was a mistake.
病院で細菌に感染しないように手を洗う。
Byouin de saikin ni kansen shinai you ni te wo arau.
I wash my hands at the hospital to avoid bacterial infection.
職人の細工は本当に見事だ。
Shokunin no saiku wa hontou ni migoto da.
The craftsman's handiwork is truly magnificent.
人間の体は何兆もの細胞でできている。
Ningen no karada wa nanchou mo no saibou de dekite iru.
The human body is made up of trillions of cells.
Memory Tip
Look at the left side of 細: the radical 糸 is a thread — thin, fragile, easy to break if you lose focus. Picture threading a needle. Hands steady, eyes squinting, every movement deliberate. That is 細 in a single image: thin, fine, and demanding full attention.
Whether you are describing a slender waist (細い), tiny print (細かい字), or microscopic bacteria (細菌), the thread holds all those meanings together. 細 = thread = thin + fine + detailed.