Abatis

thumb|right|Abatisses are used in war to keep the approaching enemy under fire for as long as possible. An abatis, abattis, or abbattis is a field fortification consisting of an obstacle formed of the branches of trees laid in a row, with the sharpened tops directed outwards, towards the enemy. The trees are usually interlaced or tied with wire. Abatis are used alone or in combination with wire entanglements and other obstacles.