The three categories of kurtosis are:
Mesokurtosis: An excess kurtosis of 0. Normal distributions are mesokurtic.
Platykurtosis: A negative excess kurtosis. Platykurtic distributions are thin-tailed, meaning that they have few outliers.
Leptokurtosis: A positive excess kurtosis. Leptokurtic distributions are fat-tailed, meaning that they have many outliers.