Sekkhasutta
Sāvatthinidānaṁ. Atha kho aññataro bhikkhu yena bhagavā tenupasaṅkami …pe… ekamantaṁ nisinno kho so bhikkhu bhagavantaṁ etadavoca: “‘sekkho, sekkho’ti, bhante, vuccati. Kittāvatā nu kho, bhante, sekkho hotī”ti?
A Trainee
At Sāvatthī. Then a mendicant went up to the Buddha … and asked him, “Sir, they speak of the one called ‘a trainee’. How is a trainee defined?”