What term describes the notch cut into a pole for mounting the crossarm?

The term that describes the notch cut into a pole for mounting the crossarm is "gain." This term is used in the context of utility poles, where a gain serves a specific purpose: it allows for the secure placement of a crossarm, which holds the wires in a stable and properly aligned position. The gain is cut into the pole to provide a snug fit that helps prevent movement or shifting of the crossarm, ensuring that the electrical lines or other components mounted on the arm remain safely in place.

Other terms provided, such as knob, bracket, and support, have different meanings and applications. A knob might refer to a rounded protrusion or handle, but it does not relate to the construction or mounting process of electrical poles. A bracket is typically a device used to hold or support structures but does not describe a cut or notch. Support is a more general term that might refer to any means of holding something up but is not specific to the notch utilized for crossarms on poles.