Trou-de-loup

n.

1.

(Mil.) A pit in the form of an inverted cone or pyramid, constructed as an obstacle to the approach of an enemy, and having a pointed stake in the middle. The pits are called also trapholes.

Noun

1.

trou-de-loup - a sloping pit with a stake in the middle used as an obstacle to the enemy

pit, quarry, stone pit