fat tail

• fat-tail, fattail

fat tail (plural fat tails)

1. A mass of fat stored in the rump of a beast as an adaptation to heat and harsh environmental conditions or selection by man.
2. The relatively high probability of a relatively extreme outcome.
3. (statistics, probability) A tail of a probability distribution with significantly higher kurtosis than a normal distribution (which has kurtosis = 0).
4. (statistics, probability) A tail of a probability distribution with infinite variance.

• (high probability of extreme outcome): heavy tail
• (tail of distribution with positive kurtosis): leptokurtosis

• fat-tailed

• black swan

• tail fat