Abatis
WordNet
noun
(1) Line of defense consisting of a barrier of felled or live trees with branches (sharpened or with barbed wire entwined) toward the enemy
WiktionaryText
Etymology
French abatis, abattis, mass of things beaten or cut down, from abattre. See abate.
Noun
- A means of defense formed by felled trees, the ends of whose branches are sharpened and directed outwards, or against the enemy.