Rank-frequency power laws in natural language, cities, earthquakes & wealth
Zipf's law: frequency ∝ 1/rank^α. For English words α≈1.0 (Zipf 1935).
George Zipf observed this in word frequencies; it appears across many complex systems.
The log-log plot should show a straight line with slope -α.
Deviations at the top (hapax legomena) reveal finite-corpus effects.