What does it mean to have a television show in syndication?

I was reading some King of Queens forums on TV.com, and it said the show went into syndication. The topic was about how long Doug & Carrie were married, saying that they sort of changed the amount of years around from 10-15 years at different times. What does it mean to put a show in syndication, and can you name some examples of syndication in The King of Queens?