In the Jātaka stories mention is made (e.g., J.iii.18; 375, 397; J.iv.113) of the Buddha when he wished to address the monks of Jetavana, asking Ānanda to summon them to the Koṭisanthāra and ordering that a seat be prepared for him at the entrance to the Gandhakuṭi.
Koṭisanthāra was probably the name given to that part of the Jetavana grounds just outside the Buddha’s own apartments. It may have been so called in reference to the fact that Anāthapiṇḍika bought the land by spreading on it ten million ¹ gold coins (kahāpaṇa) “kahāpana-
¹ A koṭi = ten million. If the coins were 1cm² this number would cover 1,000m² or a veranda of 20m x 50m (ed.)