Sthavira

(Skt, elder; Pāli, thera). One of the two main sectarian groups in early Indian Buddhism, the other being the Universal Assembly (Mahāsaṃghikas). The two groups went their separate ways at the Council of Pāṭaliputra (see Council of Pāṭaliputra I). The Sthaviras claimed to represent older more orthodox teachings that could be traced directly back to the Buddha, and they branded their opponents as heretics, although the Mahāsaṃghikas appeared to have been the more populous body. The Theravāda school claims direct descent from the Sthaviras but, although they share the same name (Thera and Sthavira being the Pāli and Sanskrit forms of the same word meaning ‘elder’), there is no historical evidence that the Theravāda school arose until around two centuries after the Great Schism which occurred at the Council of Pāṭaliputra.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)

sthávira mf(ā or ī)n. (cf. sthāvara, p. 1264) broad, thick, compact, solid, strong, powerful RV. AV. Br. MBh. Hariv
• old, ancient, venerable (○re kāle or bhāve, 'in old age') Br. &c. &c. [Page 1265, Column 3]
• m. an old man W
• (with Buddhists) an 'Elder' (N. of the oldest and most venerable Bhikshus) MWB. 184 ; 255 &c
• N. of Brahmā L
• (pl.) N. of a school (also ārya-sth○) Buddh
• (ā), f. an old woman MW
• a kind of plant L
• (am), n. benzoin L

Sanskrit-English Dictionary, by M. Monier William

gnas brtan pa

[translation-san] {LCh} sthavira

[translation-eng] {Hopkins} Sthavira

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary