noun
battlement
BAT-ul-ment/bˈætʌlmʌnt/
A low defensive wall with gaps along the top of a wall or tower.
The stone battlement alternates solid blocks with open notches above the wall walk.

Etymology
The pieces describe the result of fortifying: the word narrowed from fortification generally to an indented defensive parapet, with raised sections alternating with gaps.
In context
She sat back down on the battlement and continued watching the direction of the seal.
More examples
- The tower's battlements rise above the courtyard.
- Archers once sheltered behind the battlement's raised sections.
- The restoration preserves the damaged stone battlements.
Forms
battlement · battlements
Similar words
- parapet
- The broader protective wall, which need not have regular gaps.
- rampart
- Usually a larger defensive bank or wall.