noun, plural trous-de-loup [trood-l-oo] /ˌtrud lˈu/. Military.
  1. a conical or pyramidal pit with a pointed stake fixed vertically in the center, rows of which are dug in front of a fortification to hinder an enemy's approach, formerly used chiefly against cavalry.

Origin of trou-de-loup

1780–90; < French: literally, wolf hole Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018