tenaillon

from The Century Dictionary.

• noun In fortification, a work constructed on each side of the ravelins, like the lunettes, but differing in that one of the faces of the tenaillon is in the direction of the ravelin, whereas that of the lunette is perpendicular to it. Works of this kind are seldom adopted.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Fort.) A work constructed on each side of the ravelins, to increase their strength, procure additional ground beyond the ditch, or cover the shoulders of the bastions.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A work constructed on each side of the ravelins to increase their strength, procure additional ground beyond the ditch, or cover the shoulders of the bastions.