noun
standing watch; sentinel
Refers to a person standing guard or keeping watch, often in a military, security, or formal context.
門の前に立ち番が立っている。
A sentinel is standing in front of the gate.
彼は夜通し立ち番をした。
He stood watch all night.
Compound of 立ち (tachi, 'standing') + 番 (ban, 'watch, guard').