(grade 3 “Kyōiku” kanji)
(Can we verify(+) this pronunciation?)
From Middle Chinese 界 (MC kˠɛiH, “boundary”).
In Buddhist contexts, derived from the Middle Chinese term used as a translation of Sanskrit धातु (dhātu, “layer, stratum”).
界 • (kai)
- a bounded area or region
- a bounded group of people, a society, a world as a social grouping, such as business, celebrities, or finance
- Used both as a standalone noun, and in compounds. Use in compounds is more common in this sense.
- shizen no kai, shizenkai
- the natural world
- the art world
- the border edge of a thing
- (Buddhism) the category of a thing
- (Buddhism) the world or realm of a thing
- lines drawn between the lines of a text, as on lined writing paper
- lines drawn to lay out a draft of a piece of artwork: a sketch
- (biology, taxonomy) a kingdom
- (geology) a stratum corresponding to a geologic age
/sakapi/ → /sakaɸi/ → /sakahi/ → /sakai/
The 連用形 (ren'yōkei, “continuative or stem form”) of obsolete verb 境う (sakau, “to divide, to form a boundary between things”).
Some sources further derive the verb as Old Japanese element 境 (saka, “division, border, boundary”) + auxiliary verb ふ (fu) indicating repetition or ongoing state. However, given the semantics, this could also be analyzed as the repetitive or ongoing aspect of Old Japanese-derived verb saku with an underlying meaning of “to split apart, to separate, to put distance between”, spelled variously as 割く, 裂く, 離く, or 放く, and cognate with 咲く (saku, “to bloom”, from the idea of the blooms splitting open), 栄える (sakaeru, “to prosper”, extended from the bloom sense), 盛ん (sakan, “prospering, fluorishing”).
界 • (sakai)
- border, boundary, limits
More commonly spelled 境. Derived terms primarily use that spelling, so see that entry for more details.