dyke

In archaeology, a linear earthwork consisting of a line of bank and ditch. Most dykes in Britain are products of the post-Roman period. They may be double or occasionally treble, and were designed to serve as a boundary or frontier. Offa's Dyke along the Welsh border is an outstanding example in Britain.

Certain dykes in England may have been constructed at the end of the early Iron Age, but most date from about the 5th-9th centuries, and may have been inspired by Roman frontier works such as Hadrian's Wall and the Antonine Wall.