no.
its not like a nickname but however it can be
sydneytion witch is a not common name
Sydney's name is just Sydney. It's not spelled differently..
Sydney Fairbrother's birth name is Sydney Tapping.
Sydney Pollack's birth name is Sydney Irwin Pollack.
Sydney Newman's birth name is Sydney Cecil Newman.
Sydney Sidner's birth name is Kathryn Sydney Sidner.
Robin Sydney's birth name is Robin Sydney Heymsfield.
Sydney Spies's birth name is Sydney Elizabeth Spies.
Sydney Streeter's birth name is Sydney Stanley Streeter.
Sydney Penny's birth name is Sydney Margaret Penny.
Sydney Gulizio's birth name is Sydney Jordan Gulizio.
Sydney Greenstreet's birth name is Greenstreet, Sydney Hughes.
Sydney Ackman's birth name is Sydney Ryan Ackman.