Definition of "boyau" []

• In military fortification, a trench or ditch covered with a parapet that provides communication between two trenches, particularly the rear and front lines. Boyaus were typically constructed in a zigzag pattern to prevent exposure to direct enemy fire from the front. (noun)
• A line, drawn winding about, in order to enclose several tracts of land, or to attack some works. (noun)

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• "We have no direct evidence how the embryo is formed, yet no one doubts but that it is brought about by the agency of the boyau, which is a cell containing grumous molecular matter."
• "Just as we neared the crest of the hill, at a notice bearing the legend, "Keep below," the whole party entered a deep "boyau" leading right up to the trenches in front, from which branched off various passages to the gun pits, or butts, as we used to call them."
• "_Jacques Martin, soldat au 170e d'infanterie, grenadier d'élite, au cours des combats du 26 et du 27 novembre, 1916, a, par son mépris du danger et par son ardeur, assuré la progression dans un boyau défendu pas à pas par l'ennemi."