theravAdaNca

Я вообще склоняюсь к тому, что самоназвание не связано, со словом тхера - в смысле старший монах, а скорее означает старейшее учение, в смысле самая древняя школа, идущая от самого Будды, чтобы подчеркнуть первоприемственность и отличие от более новодельных школ.

Вообще, эта фраза во многих сутрах встречается: https://www.google.ru/search?q=%C3%B1%C4%81%E1%B9%87av%C4%81da%C3%B1-ca+vad%C4%81mi+therav%C4%81da%C3%B1-ca,&ie=utf-8

There were, besides, many other great Theras who were original depositaries (of the Faith). By these and other saintly Theras who had fulfilled their duties, to the number of five hundred, was the collection of the Dhamma and the Vinaya made; because it was collected by the Theras, it is called the doctrine of the Theras (theravāda). They composed the collection of the Dhamma and of the whole Vinaya by consulting Upāli about the Vinaya and learned Ānanda about the Dhamma ... who had obtained perfection in the true Doctrine, had learned the Dhamma and Vinaya from the Jina; ... Having received the perfect word (of Buddha), the first (among doctrines), from the first (among teachers), these Theras and original depositaries (of the Faith) made the first collection. Hence this doctrine of the Theras is also called the first (or primitive) doctrine. The most excellent Theravāda remained pure and faultless for a long time, for ten times ten years.

https://archive.org/stream/dpavasaanancien00oldegoog#page/n142/mode/2up/

"Now since the canon was compiled by the theras it was called the Thera tradition.' The theras who had held the First Council and had (thereby) brought great blessing to the world, having lived their allotted span of life, entered, all, into nibbana."

http://books.lakdiva.org/mahavamsa/chap003.html