Second-in-command and Sub

Second-in-command noun - Someone who relieves a commander.

Sub and second-in-command are semantically related. in assistant topic. In some cases you can use "Sub" instead a noun phrase "Second-in-command".

Sub noun - A large sandwich on a long split roll.

Second-in-command and sub are semantically related. Sometimes you can use "Second-in-command" instead a noun "Sub".