The story
Named after Carl Friedrich Gauss, who was aware of a version of the theorem but never published it, and Pierre Ossian Bonnet, who published a special case in 1848.
Etymology from Wiktionary, CC BY-SA 4.0.
Gauss-Bonnet theorem
Today it means: An important statement about surfaces in differential geometry, connecting their geometry (in the sense of curvature) to their topology (in the sense of the Euler characteristic). Full definition →