Sentence:  Technical terms like ferrite, perlite, graphite, and hardenite were bandied to and fro, and when Paget glibly brought out such a rare exotic as ferro-<WSD>molybdenum</WSD>, Benson forgot that he was a master ship-builder, […] 
Meaning of the word marked with <WSD> tags:  A chemical element ("symbol" Mo) with an atomic number of 42: a silvery metal, not found as a free element, used in steel alloys.