noun
empty lot; vacant plot of land
Refers to a cleared piece of land with no buildings, often after demolition or before construction.
古い家を取り壊して、その土地を更地にした。
We demolished the old house and turned the land into an empty lot.
更地のままにしておくと固定資産税が高くなる。
If you leave it as a vacant plot, the property tax will be higher.
空き地 is a general term for any unused open space, while 更地 specifically means land that has been cleared of buildings.
Compound of 更 (さら, 'newly, afresh') and 地 (ち, 'land'). The exact historical derivation is uncertain, but the term is conventionally associated with land that has been made bare or renewed.