1British (now chiefly English regional). Originally: arable land lying fallow. Later (also): specifically arable land sown with grass for more than two years.
2US rare Land that has been in cultivation for a long time, or exhausted by a long period of cultivation.
3rare With the, and frequently with capital initials. In the language of colonists or those living or travelling abroad: a country of origin, especially. Britain or Ireland. Compare "old country".
(Usually oldland.) Land which lies behind a coastal plain of more recent origin, especially where the coastal plain has been built up from sedimentary material derived from that same land. Also: an area of very ancient crystalline rocks, especially when reduced to low relief.
Old English; earliest use found in Bald's Leechbook. From old + land.