The story
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A scalar λ, such that there exists a non-zero vector x (a corresponding eigenvector) for which the image of x under a given linear transformation A is equal to the image of x under multiplication by λ; i.e. Ax=λx. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.