Also 8–9 berme, 9 birm. [a. F. berme, a. MDu. and Ger. berme, in mod.Du. berm, in same sense; prob. cognate w. ON. barmr brim, edge, border of a river, the sea, etc.]
1. A narrow space or ledge; esp. in Fortif. a space of ground, from 3 to 8 feet wide, sometimes left between the ditch and the base of the parapet.
1729. Shelvocke, Artillery, IV. 197. Round which shall be formed a Berm or Ledge, for the conveniently ranging of certain Paper Tubes or Cases.
1775. R. Montgomery, in Sparks, Corr. Amer. Rev. (1853), I. 470. By the time we arrived there, the fraise around the berme would be destroyed, the rampart in a ruinous state.
1816. C. James, Mil. Dict. (ed. 4), 248/2. Berm … is to prevent the earth from rolling into the ditch, and serves likewise to pass and repass. As it is in some degree advantageous to the enemy, in getting footing, most of the modern engineers reject it.
1850. Alison, Hist. Europe, X. lxviii. § 49. 335. The ladders … enabled them to reach an intermediate ledge or berm.
2. Berm-bank, the bank of a canal opposite the towing-path. [? Actually used only in U.S.A.]
1854. N. & Q., Ser. I. X. 12/2. [A writer from Philadelphia] The bank of a canal opposite to the towing-path is called the birm-bank.
1877. Engineer, 3 Aug., 89/1. To lay a rail upon the berme bank (the bank opposite the towing path).
