Also boyeau. [F. boyau ‘the alimentary canal,’ and as below:—OF. boel: see BOWEL.] Fortif. ‘A branch of a trench; a zigzag; a trench in rear of a battery, forming a communication with the magazine; a small gallery of a mine.’ Stocqueler, Milit. Encycl., 1853, 41/2.
1847. in Craig.
1862. F. Griffiths, Artil. Man. (ed. 9), 263. Zig-zags, or Boyeaux of communication, are trenches made for the approaches from the parallels to the besieged place.
