Third lieutenant
East-European ranks
A few non-English-speaking militaries maintain a lower rank, frequently translated as "third lieutenant". The rank title may actually translate as "second lieutenant", "junior lieutenant", "sub-lieutenant" or "ensign". The Soviet Union used three ranks of lieutenant, and Warsaw Pact countries similarly standardized their ranking system. Some of the former Soviet and Warsaw Pact nations have now discarded the third rank while many retain it like Bulgaria.
American brevet second lieutenants
Throughout the 19th century and until as late as World War II[4] the United States Army sometimes referred to brevet second lieutenants as "third lieutenants." These were typically newly commissioned officers for which no authorized second lieutenant position existed. Additionally, the Confederate States Army also used "third lieutenant", typically as the lowest ranking commissioned officer in an infantry company.
http://en.wikipedia.org/wiki/Lieutenant