Meaning
遮 means to block, intercept, obstruct, or screen off. Picture the exact instant a crossing gate drops, a cloud slides over the sun, or someone throws up a hand mid-sentence — that act of cutting something off mid-flow is what 遮 captures. What sets it apart from 防 (to prevent) is emphasis on active interruption: something was moving freely, and now it isn't.
遮 is built from two components. The radical 辶 (しんにょう) signals movement along a road or path. The upper element 庶 (しょ) originally depicted a cooking hearth with spreading flames and later came to mean "various" or "common." Together they suggest something vast thrown across a road, stopping everything cold — a broad barricade blocking all passage. 庶 also supplies the on'yomi reading シャ.
遮 has 14 strokes and sits outside the elementary school curriculum as a grade 8 character, introduced at the secondary level. It is classified under JLPT N1. In practice, 遮 turns up regularly in construction specs, real estate listings, product descriptions for energy-saving materials, and journalism — wherever blocking light, sound, heat, or traffic calls for a precise term.
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi is シャ (sha), used almost exclusively in compound words (熟語, jukugo). シャ dominates formal and technical contexts — construction, electrical engineering, optics, acoustics, military writing. If you see 遮 in a compound, it reads シャ.
- 遮断 (shadan) — interception, cutoff, severance; used in contexts ranging from cutting off electricity to blocking a road or severing communication
- 遮光 (shakou) — light-blocking, shading, sun protection; commonly seen in the phrase 遮光カーテン (blackout curtains)
- 遮蔽 (shahei) — shielding, screening, masking; appears in military, medical, and engineering contexts involving protective barriers
- 遮音 (shaon) — soundproofing, acoustic insulation; frequently used in construction and real estate descriptions
- 遮熱 (shanetsu) — heat shielding, thermal insulation; found in building materials, automotive glass, and energy-efficiency products
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi さえぎ・る (saegi-ru) is a Group 1 verb (五段動詞). Conjugation: さえぎる (dictionary form) → さえぎった (past) → さえぎって (te-form). Where the シャ compounds lean formal and technical, さえぎる sounds immediate — the word you'd actually reach for when someone cuts you off mid-sentence or steps into your line of sight.
- 遮る (saegiru) — to block, to intercept, to interrupt (the base form)
- 視界を遮る (shikai wo saegiru) — to obstruct one's field of vision
- 言葉を遮る (kotoba wo saegiru) — to cut someone off mid-sentence, to interrupt
Common Words & Compounds
Every compound built on 遮 shares one thread: something is being stopped. Grouping them by what gets blocked makes even unfamiliar ones easy to read at a glance — know 遮音 and 遮音材 follows immediately.
Blocking & Cutting Off
- 遮断 (shadan) — interception, severance, cutoff (of electricity, traffic, communication, or diplomatic ties)
- 遮断機 (shadanki) — railroad crossing gate; the mechanical arm that lowers across the road before a train passes
- 遮断器 (shadanki) — circuit breaker; an electrical device that breaks a circuit to prevent overload (written with 器 rather than 機)
- 遮蔽 (shahei) — shielding, screening, concealment; used in military camouflage, radiation protection, and signal blocking
- 遮蔽物 (shaheibutsu) — a shielding object, cover, or protective screen
Light & Sound
- 遮光 (shakou) — light-blocking, shading (as in UV protection or room darkening)
- 遮光カーテン (shakou kaaten) — blackout curtain; curtains designed to completely block outside light
- 遮光ガラス (shakou garasu) — tinted glass, UV-blocking glass used in vehicles and buildings
- 遮音 (shaon) — soundproofing, sound insulation
- 遮音材 (shaonzai) — soundproofing material used in walls, floors, and ceilings
- 遮音性 (shaonsei) — soundproofing quality or performance rating, commonly listed in apartment specifications
Heat & Environment
- 遮熱 (shanetsu) — heat shielding, thermal insulation; used to reflect radiant heat away from buildings or vehicles
- 遮熱塗料 (shanetsu toryou) — heat-reflective paint applied to rooftops to lower interior temperatures in summer
- 遮水 (shasui) — waterproofing, water barrier (used in dam liners and underground construction)
- 遮風 (shafuu) — windbreak, wind shielding (trees or barriers planted to block prevailing winds)
Example Sentences
彼は私の話を遮って、自分の意見を述べ始めた。
Kare wa watashi no hanashi wo saegitte, jibun no iken wo nobe-hajimeta.
He cut off what I was saying and began stating his own opinion.
厚い雲が太陽の光を遮り、辺りが急に暗くなった。
Atsui kumo ga taiyou no hikari wo saegiri, atari ga kyuu ni kuraku natta.
Thick clouds cut off the sunlight, and everything around us went dark at once.
遮光カーテンを使うと、朝の光を完全に防ぐことができる。
Shakou kaaten wo tsukau to, asa no hikari wo kanzen ni fusegu koto ga dekiru.
Blackout curtains let you block out the morning light completely.
電車が来る前に、踏切の遮断機が下りた。
Densha ga kuru mae ni, fumikiri no shadanki ga orita.
Before the train arrived, the crossing gate dropped into place.
この壁は遮音性能が優れており、外の騒音がほとんど聞こえない。
Kono kabe wa shaon seinou ga sugurete ori, soto no souon ga hotondo kikoenai.
This wall has excellent soundproofing — outside noise barely comes through.
停電で電力が遮断され、工場の機械が一斉に止まった。
Teiden de denryoku ga shadan sare, koujou no kikai ga issei ni tomatta.
A power outage cut the electricity, and every machine in the factory stopped at once.
彼女は手で目を覆い、まぶしい日差しを遮った。
Kanojo wa te de me wo ooi, mabushii hizashi wo saegita.
She cupped her hand over her eyes, shielding them from the blinding glare.
会議の途中で発言を遮るのは、礼儀に反することだ。
Kaigi no tochuu de hatsugen wo saegiru no wa, reigi ni han suru koto da.
Cutting someone off during a meeting is a breach of proper etiquette.
遮熱塗料を屋根に塗ることで、夏の室温を効果的に下げられる。
Shanetsu toryou wo yane ni nuru koto de, natsu no shitsuon wo koukateki ni sagerareru.
Applying heat-reflective paint to the roof can noticeably lower indoor temperatures in summer.
Memory Tip
Break 遮 into its two parts. At the bottom-left sits 辶, the movement radical — a road or path. Above it is 庶, which suggests something vast and widespread spreading out in all directions. Put them together: an enormous crowd swarming across a road, blocking everything in its path. That image is exactly what 遮 means.
For the on'yomi シャ (sha), link it to the English word shade: "shade = シャ = block the light." For さえぎる (saegiru), picture someone flinging out an arm with a sharp "sae — stop!" — a physical gesture that cuts off whatever was flowing. Two images, two readings, one kanji sorted.