failure mode (1) (general)

The way in which a failure mechanism manifests itself in a failing component.

(2) (in a BGA ball shear test): The type or location of failure observed after the solder ball is sheared.

References: 

JEP122C, 3/06
JESD91A, 8/01
JESD671-A, 6/97

JESD22-B117A, 10/07