俱舍論頌疏論本 1.28

1.28

言正釋品名者，族義、持義、性義名界，此品廣明，故名分別。問：「此品亦明蘊、處，何故以界標名？」答：「此品廣以二十二門分別十八界故，以界標名。蘊、處不爾，故不標也。」

As for directly explaining the chapter titles: the meanings of clan/lineage (*gotra*), bearing/maintaining (*dhāraṇa*), and intrinsic nature (*svabhāva*) are called *dhātu* ("realm"); this chapter explains them extensively, and is therefore called "Analysis" (*vibhaṅga*). Question: "This chapter also explains the aggregates (*skandha*) and sense bases (*āyatana*); why is it titled after realms (*dhātu*)?" Answer: "Because this chapter extensively analyzes the eighteen realms through twenty-two gates, it is titled after realms. The aggregates and sense bases are not treated in this manner, and therefore the chapter is not titled after them."