What does the p mean in p-toluenesulfonic acid?

I am studying organic chemistry and my professor never mentioned what the p means.

Mike A2011-01-17T09:29:06Z

Favorite Answer

It means "para". The three isomers are named o or ortho where the methyl and the sulphonate groups are on adjacent carbons, m or meta where there is one unsubstituted carbon between them and para where there are two unsubstituted carbons between them.