Abatis

an obstacle or barricade of trees with bent or sharpened branches directed toward an enemy.
a barbed wire entanglement used as an obstacle or barricade against an enemy.
Historical Examples

“Orderly, take the company back into the abatis, and look for the boys,” ordered Capt. McGillicuddy.
Si Klegg, Book 6 (of 6) John McElroy

He got his smashed with a bullet comin’ through the abatis, and’s bin mournin’ about ’em ever since.
Si Klegg, Book 6 (of 6) John McElroy

Bring in that man that skulked when the boys were going for that abatis.
Si Klegg, Book 6 (of 6) John McElroy

He also carried in and made an abatis between himself and the enemy.
Personal Memoirs of U. S. Grant, Complete Ulysses S. Grant

Again, at double-quick, the column went forward to within fifty yards of the fort, to meet there another line of abatis.
The Black Phalanx Joseph T. Wilson

The Rebels tore away their own abatis, and in less than a minute were inside the fort.
The Boys of ’61 Charles Carleton Coffin.

They were now exactly opposite the Death Angle and only a few yards from the abatis.
Vermont riflemen in the war for the union, 1861 to 1865 William Y. W. Ripley

Without making the least noise, Si reached the edge of the abatis.
Si Klegg, Book 6 (of 6) John McElroy

Between these pits and the Fort were wire entanglements, running from stump to stump, and also an abatis.
The Atlantic Monthly, Volume 18, No. 105, July 1866 Various

He was sure that this led through the abatis, and the rebel was coming down it.
Si Klegg, Book 6 (of 6) John McElroy

noun (fortifications)
a rampart of felled trees bound together placed with their branches outwards
a barbed-wire entanglement before a position
n.

“defense made of felled trees,” 1766, from French abatis, literally “things thrown down,” from Old French abateis, from abattre “to beat down, throw down” (see abate).