A barrier is, stripped to its essence, a bar across a path. The word comes from Old French barriere, built on barre ('a bar or rod'), which traces to Vulgar Latin *barra — a word whose deeper origin remains debated, with Celtic and pre-Indo-European substrates both proposed. The physical image is ancient and universal: a wooden bar placed across a road to halt travellers, collect tolls, or defend a position. English borrowed it in the fourteenth century, initially for actual fences and fortifications before extending it to any obstacle, physical or abstract. The same root *barra generated a remarkable family of English words. 'Bar' itself covers everything from drinking establishments (originally the barrier between server and customer) to the legal profession (the bar separating court from public). 'Barricade' intensifies the blocking. And 'embargo' — from Spanish embargar ('to obstruct') — applies the bar to trade between nations.