Redoubt

Redoubt (Fr. redoute, from Med. Lat. reductus, a place of retreat, refuge, reducere, lead back, retire; the intrusive b is  due to the O. Fr. redoubter, to fear, Lat. dubitare, to doubt), a term in fortification for a small closed work of plain trace, generally used in conjunction with lines of infantry trenches (see Fortification And Siegecraft). The tern reduit " (Fr. reduit), often confused with " redoubt," is only used for a keep or interior refuge for the garrison of a larger work, corresponding, on a small scale, to the citadel of a fortress.