Normal Distribution
Etymology
Studied by de Moivre, Laplace, and Gauss (hence “Gaussian”), it was dubbed “normal” in the late 19th century by figures like Galton and Pearson, from Latin “norma” (a carpenter’s square, a rule). The name unfortunately implies other distributions are abnormal, which they are not.
noun phrase · /NOR-muhl dis-truh-BYOO-shuhn/
The symmetric bell-shaped curve in which most values cluster near the average and extremes are rare.
What it names
It is the default mental model for variation — and knowing when data are NOT normal is half of statistical literacy.
Example
Human heights follow a roughly normal distribution, but wealth does not — assuming the bell curve for income leads straight to bad predictions.
Related idea
The “bell curve” is only one distribution among many; phenomena governed by a power law, like city sizes or wealth, have long fat tails the normal curve badly underestimates.