The Collaborative International Dictionary of English v.0.48:

Leningrad \Leningrad\ prop. n.
   A city in the European part of Soviet Russia; the former
   capital of Russia. The name was formerly St. Petersburg and
   Petrograd, and was changed back to Saint Petersburg
   (Sankt Peterburg in Russian) in 1992.

   Syn: St. Petersburg, Peterburg, Petrograd, Saint Petersburg.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

Saint Petersburg
    n 1: a city in western Florida on Tampa Bay; a popular winter
         resort [syn: St. Petersburg, Saint Petersburg]
    2: a city in the European part of Russia; 2nd largest Russian
       city; located at the head of the Gulf of Finland; former
       capital of Russia [syn: St. Petersburg, Leningrad,
       Peterburg, Petrograd, Saint Petersburg]