āvāsa (Pāli). A site occupied by monks during the rainy season retreat. The āvāsa marks the geographical boundary within which temporary structures known as vihāras were constructed to provide shelter from the rains. In the earliest times the sites were abandoned after the rains but in the course of time there was a tendency for them to develop into permanent monastic residences.

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

āvāsa : [m.] home; dwelling place.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Āvāsa [Sk. āvāsa; ā + vas] sojourn, stay, dwelling, living; dwelling -- place, residence Vin i.92; D iii.234; S iv.91; A ii 68, 168; iii.46, 262; Sn 406; Dh 73 (cp. DhA ii.77); Nd1 128; J vi.105; Dhs 1122; Pug, 15, 19, 57; KhA 40; DhA i.177 (āvāsaŋ ālimpeti: read āvāpaŋ); PvA 13, 14, 36; VvA 113; Sdhp 247. -- anāvāsa (n. & adj.) uninhabited, without a home; an uninhabited place A iv.345; J ii.77; Pv ii.333; PvA 80 (= anāgāra); VvA 46.
   -- kappa the practice of (holding Uposatha in different) residence (within the same boundary) Vin ii.294, 300, 306; Dpvs iv.47, cp. v.18. -- palibodha the obstruction of having a home (in set of 10 Palibodhas) KhA 39; cp. Vism 90 sq. -- sappāyatā suitability of residence Vism 127.

Pali-English Dictionary, TW Rhys Davids, William Stede,

āvāsa: m. 住[處]

巴漢辭典 編者：(斗六) 廖文燦