Sentence:  Originally, doubtless, that petty-officer's function was the instruction of the men in the use of arms, sword or cutlas. But very long ago, owing to the advance in <WSD>gunnery</WSD> making hand-to-hand encounters less frequent and giving to nitre and sulphur the preeminence over steel, that function ceased 
Meaning of the word marked with <WSD> tags:  The design and manufacture of guns, particularly those of a large caliber.