Fat-tailed distribution

A 'fat-tailed distribution' is a way of describing the spread of values in a set of data. The 'tails' of the fat-tailed distribution are the two ends of the spread, where the data either shows values that only occur very rarely (at the left end) or values that occur frequently (at the right end). This means that the fat-tailed distribution has more values at the extremes than a normal distribution. This is why it is called a 'fat-tailed' distribution - it has a larger number of values in the 'tails' than most distributions.