Power Law
Etymology
The term joins "power" — the mathematical sense of a number raised to an exponent, itself a calque of Greek "dynamis" through Latin — with "law" for a regular relationship. It names distributions where one variable scales as a fixed power of another, so magnitude and rarity trade off smoothly across many orders. It rose to prominence through early-twentieth-century studies of incomes, city sizes, and word frequencies.
noun phrase · /POW-er law/
A relationship in which one quantity varies as a fixed power of another, producing distributions where a tiny few dominate a vast many.
What it names
Reach for it when a phenomenon is radically unequal — city sizes, book sales, wealth, earthquakes — and averages mislead because there is no typical case, only a steep few and a long many.
Example
Ninety percent of the app’s revenue came from a handful of whales — a textbook power law, not a bell curve.
Related idea
Distinct from the Matthew effect, which is one mechanism (accumulated advantage) that can generate such a distribution; the power law is the resulting shape, agnostic about how it arose.