What was the Pontiac Wide Track?

A friend of mine has a both a 1971 Pontiac Firebird and a 65 Lemans-While I have an 65 Chevelle and my cousin an 19 camaro(2nd gen.) Is there any real difference? What is wide track? Was it just a marketing ploy for Pontiac? IF I can't find a real answer I will just have to go out and Measure in this frigid weather.