Emily Dickinson Lexicon

BUL'WARK, n. [Sw. bolvärck; D. bolwerk; Ger. bollwerk; Dan. bolværk; from D. bol, plump and a ball, Sw. bula, W. bal, a protuberance, and work; a projecting or outwork. Fr. boulevard; Sp. and Port. baluarte; It. baluardo.]

1. In fortification, a bastion, or a rampart; a mound of earth round a place, capable of resisting cannon shot, and formed with bastions, curtains, &c. – Encyc.
2. A fortification; also, any means of defense; as, a navy is the bulwark of a nation.
3. That which secures against an enemy or external annoyance; a screen or shelter; means of protection and safety. Salvation will God appoint for walls and bulwarks. – Is. xxvi.