1911 Encyclopædia Britannica/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 term “ reduit " (Fr. réduit), 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.