earthen wall; earthwork; embankment
Refers to defensive earthen ramparts or embankments, especially in historical fortifications.
城の周りには土塁が築かれていた。
Earthen walls were built around the castle.
この遺跡には古い土塁が残っている。
Old earthworks remain at this archaeological site.
Compound of 土 (do, 'earth') and 塁 (rui, 'rampart, fort'). The term is straightforward and describes an earthen defensive wall.