Wordnet 3.0
NOUN (1)
1.
a sloping pit with a stake in the middle used as an obstacle to the enemy;
The Collaborative International Dictionary of English v.0.48:
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]
WordNet (r) 3.0 (2006):
trou-de-loup
n 1: a sloping pit with a stake in the middle used as an
obstacle to the enemy