What is "caponiere"

Caponiere \Cap`o*niere"\, n. [F. caponni[`e]re, fr. Sp. caponera, orig., a cage for fattening capons, hence, a place of refuge; cf. It. capponiera. See Capon.] (Fort.) A work made across or in the ditch, to protect it from the enemy, or to serve as a covered passageway.

n. (context military historical English) A work made across or in the ditch, to protect it from the enemy, or to serve as a covered passageway.