embattled grady line

This heraldic term refers to a line that both zig-zags and is "stepped", or crenellated, like a castle battlement.
It appears in heraldic charges, and as a decorative border in manuscripts.

Source: The Book Of Traceable Heraldic Art, https://heraldicart.org/embattled/#embattled-grady-line.
Shared under a Creative Commons BY-SA 4.0 licence, https://creativecommons.org/licenses/by-sa/4.0/.