Third officer
A third officer was an bridge officer position aboard a starship that was fourth in line for command of the vessel after the captain, first officer, and second officer. 

In 2375, during the waning days of the Dominion War, Dahar Master Kor was given an assignment as third officer aboard the . ()

In 2377, Tom Paris stated to Chakotay that it had just occurred to him that "with you in command and Tuvok off the ship, that makes me acting first officer. Technically speaking," and therefore third officer. () That had also been the previous case for Paris, when he was left in command of Voyager, when Janeway, Chakotay, and Tuvok were off ship or away from the bridge. ()

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de:Dritter Offizier
es:Tercer Oficial
ja:第三副長
nl:Derde officier
Titles
Military ranks