оплот

bulwark; stronghold; backstop; citadel; pillar; rampart; support; propugnaculum; bastion; redoubt; palladium; castle; fastness; stalwart (Mykael); beacon (из кинофильма "Дьявол носит Prada" (2006) • beacon of elegance and grace Mr. Wolf); fortress (a military stronghold, especially a strongly fortified town lunovna); fence; mound; mount

mainstay; tower; buttress (figurative) Anything that supports or strengthens epoost)