俱舍論疏 24.15

24.15

論「間謂間隔至說名一間」，此釋一間名也。《正理論》云「所言間者是隙異名。謂彼位中由有一隙，容一生故，未得涅槃。」「有一間者說名一間」者，此則釋人名一間也。

The commentary states: "'Interval' means obstruction … hence called a single-interval practitioner," which explains the name 'single-interval practitioner'. The Nyāyānusāra states: "The word 'interval' is another name for a gap. It means that in that stage, because there is one gap that accommodates one birth, one has not yet attained nirvāṇa." "Having one interval, one is named a single-interval practitioner": this explains the person named a single-interval practitioner.