1911 Encyclopedia Britannica
Or ABBATTIS (a French word meaning a heap of material thrown), a term in field fortification for an obstacle formed of the branches of trees laid in a row, with the tops directed towards the enemy and interlaced or tied with wire. The abatis is used alone or in combination with wire-entanglements and other obstacles.
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Chisholm, Hugh, General Editor. Entry for 'Abatis'. 1911 Encyclopedia Britanica. https://www.studylight.org/encyclopedias/eng/bri/a/abatis.html. 1910.