The story
Named after Joseph Louis Lagrange, who published on the topic in 1795, though the method was first discovered in 1779 by Edward Waring.
Etymology from Wiktionary, CC BY-SA 4.0.
Lagrange polynomial
Today it means: For a given set of points (x_j,y_j) with no two x_j values equal, the polynomial of lowest degree that assumes at each value x_j the corresponding value y_j, so that the functions coincide at each point. Full definition →