Sentence:  Near the end of his <WSD>service</WSD> he wrote that when the war was over he was going to buy two pups , name one of them `` fall-in '' and the other `` close-up '' , and then shoot them both , `` and that will be the end of ' fall-in ' and ' close-up '' ' . 
Meaning of the word marked with <WSD> tags:  a force that is a branch of the armed forces