choropleth map

Meanings

1. A thematic map in which the distribution of some property is shown using different colours.

Etymology

From Ancient Greek χώρα (khṓra, “location”) + πλῆθος (plêthos, “a great number”) + English map. First proposed in 1938 by American geographer John Kirtland Wright to mean "quantity in area," although maps of the type have been used since the early 19th century.