dhātu, intp. by 界 field, area, sphere; 體 embodiment, body, corpus; 性nature, characteristic. It means that which is placed or laid; a deposit, foundation, constituent, ingredient, element; also aśarīra, or relic of Buddha The twodhātus are the conditioned and unconditioned, phenomenal and noumenal; the three are the realms of desire, of form, and of the formless; the four are earth, water, fire, and air; the six add space and intelligence; the eighteen are the twelveāyatanas, with six sensations added.
馱都 此云界。百法疏云：界是因義。中間六識，藉六根發。六境牽生，與識為因，故名為界。法界次第云：界以界別為義。此十八法，各有別體，義無渾濫，故名十八界。若根相對，即有識生。識以識別為義，識依於根，能別於塵，故通名識。由此根、塵、識三，各有六法，成十八界。此三科法，如俱舍云：聚生門種族，是蘊處界義，愚根樂有三，故說蘊處界。釋曰：愚三者，一、愚心，為說五陰，則開心為四，合色為一。二、愚色，為說十二處，則開色為十處半，謂五根、五塵及法塵少分；合心為一處半，謂意根及法塵少分。三、愚心及色，為說十八界，則更開心為七界半，謂六識、意根、法塵少分。皆言愚者，迷也。根三，謂上、中、下根，樂三，謂略、中、廣。皆如次配三科法。
梵語也此云法界界即體也