rank-size rulenoun [ S ]
ukusalso rank-size law, rank-size distribution ECONOMICSthe principle that many things all over the world, for example the sizes of cities or businesses, or how rich people are, follow the same pattern in relation to their rank on a list:
According to the rank-size rule, a rank 3 city would have ⅓ the population of a country's largest city, a rank four city would have ¼ the population of the largest city, and so on.