breastwork

Breastwork is a transparent English compound: breast + work. The word appears in the sixteenth century. A breastwork is a low, temporary defensive wall — typically earthen — built high enough to protect a standing or kneeling soldier from the chest down. The name is a description. It is a work that reaches your breast.

Breastworks differ from parapets in their informality. A parapet is part of a permanent fortification. A breastwork is thrown up in the field — dug from earth, piled from logs, assembled from whatever is available. Civil War soldiers built breastworks before virtually every engagement. The order 'entrench' meant 'build a breastwork.' By 1864, no army in the American Civil War moved without building field fortifications as a reflex.

The Battle of Bunker Hill (1775) — actually fought on Breed's Hill — was a battle over a breastwork. American militia built an earthen breastwork overnight and defended it against three British assaults. The famous instruction 'don't fire until you see the whites of their eyes' was a breastwork directive — defenders behind a low wall can afford to wait because the wall absorbs the first volley.

Breastworks evolved into trenches in World War I. The logic was identical — protect the soldier's body below firing height — but the scale changed. What was a single wall became a system of interconnected ditches stretching from Switzerland to the English Channel. The breastwork became the Western Front.