Sentence:  In fact, the visible appearance of the iron is a symbol; it is not what it ultimately is. To take an analogy we are given a ten-<WSD>rupee</WSD> note. He knows it truly who at sight recognizes the piece of paper as a symbol of unity that represents ten separate silver coins. 
Meaning of the word marked with <WSD> tags:  The common name for the monetary currencies used in modern India, Mauritius, Nepal, Pakistan, the Seychelles, or Sri Lanka, often abbreviated ₨.