'Trou-de-loup' definitions:

Definition of 'trou-de-loup'

(from WordNet)
noun
A sloping pit with a stake in the middle used as an obstacle to the enemy

Definition of 'Trou-de-loup'

From: GCIDE
  • Trou-de-loup \Trou"-de-loup"\, n.; pl. Trous-de-loup. [F. trou hole + de of + loup wolf.] (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. [1913 Webster]