The story
Developed by French mathematician Nicolas Auguste Tissot in the 19th century.
Etymology from Wiktionary, CC BY-SA 4.0.
Tissot's indicatrix
Today it means: A mathematical contrivance used to characterize local distortions due to map projection. It is the geometry that results from projecting a circle of infinitesimal radius from a curved geometric model, such as a globe, onto a map. Full definition →