From Longman Dictionary of Contemporary Englishsecond-in-commandˌsecond-in-comˈmand noun [countable] POSITION/RANKthe person who has the next highest rank to the leader of a group, especially in a military organization
Examples from the Corpus
second-in-command• Also on trial was Milko Balev, Zhivkov's former second-in-command.• Bureaucrats make good second-in-commands but poor generals.• Not surprisingly, this was piloted by Admiral Sean Hellewell, second-in-command of the club.• Gerard Faggionato, who had acted as the department's director, becomes his second-in-command.• His second-in-command re-divided the men and sent them back for a second search of the places they had searched before.• Morris Landlord, 36, the Etireno's second-in-command, said there had been no unaccompanied children on board.• As the second-in-command under a nearly incapacitated president, many observers had expected her to take center stage. 