āraṇya-vāsī (Sanskrit). A forest-dweller; name given to monks who choose to emulate the lifestyle of the Buddha and the early Saṃgha by dwelling in sparsely populated rural areas. The term especially applies to those who observe the stringent austerities known as dhutangas. Forest-dwelling monks who practise meditation as opposed to devoting themselves to the study of texts have always existed and may have played a greater part in the formation of the early Mahāyāna than has hitherto been appreciated. After having been of minor importance for many centuries, the tradition of living in seclusion has been revived with considerable success in certain south-east Asian countries such as Thailand.

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