1. standing guard or keeping watch as a sentinel
Usage: present participle of sentinel

Examples

• The soldier was sentinelling the entrance to the camp.
• Guards have been sentinelling the palace gates all night.
• The lighthouse keeper spent his days sentinelling the rocky coastline.
• She found herself sentinelling the children while they played in the yard.
• The dog was sentinelling the house while the family was away.
• Ancient warriors were sentinelling the mountain passes against invaders.