The story
After German mathematician Carl Gustav Jakob Jacobi (1804-1851).
Etymology from Wiktionary, CC BY-SA 4.0.
Jacobi identity
Today it means: Given a binary operation × defined on a set S which also has additive operation + and additive identity 0, the property that a × (b×c) + b × (c×a) + c × (a×b) = 0 for all a, b, c in S. Full definition →