A field fortification (such as a trench or a mound) made of earth. Earthworks were used to protect troops during battles or sieges, to protect artillery batteries, and to slow an advancing enemy.

"mounds of earth thrown up for some purpose, especially as a military fortification," 1630s, from earth + work (n.). In this sense Old English had eorðbyrig "mound, embankment;" Ol [..]

Artistic manipulation of the natural landscape, typically though not exclusively enacted on a large scale. Related: Ana Mendieta. Nile Born. 1984 Robert Smithson. Corner Mirror with Coral. 1969.

constructed mound, wall, or other feature made of soil.

(n) an earthen rampart

These are archaeological banks and ditches, bump and humps in the landscape as they survive. They might stand only a few centimetres above ground level, or be elaborate large-scale constructions, such [..]

 - A type of contemporary art begun in the 1960's and '70's, which uses the landscape, or environment, as its medium, either by using natural forms as the actual work of art, o [..]

Any structure made from earth; especially an embankment or rampart used as a fortification