Sentence:  Ancient Sparta used iron <WSD>bars</WSD> instead of handy coins in more valuable alloy, to physically discourage the use of money. 
Meaning of the word marked with <WSD> tags:  A solid metal object with uniform (round, square, hexagonal, octagonal or rectangular) cross-section; in the US its smallest dimension is .25 inch or greater, a piece of thinner material being called a strip.