advance guard

n.
A detachment of troops sent ahead of a main force to reconnoiter and provide protection.

A detachment sent ahead of the main force. Its functions are to ensure the main body's uninterrupted advance, to protect the main body against surprise, facilitate the advance by removing obstacles and repairing roads and bridges, and to cover the deployment of the main body if it is committed to action.

See the Introduction, Abbreviations and Pronunciation for further details.

(DOD) Detachment sent ahead of the main force to ensure its uninterrupted advance; to protect the main body against surprise; to facilitate the advance by removing obstacles and repairing roads and bridges; and to cover the deployment of the main body if it is committed to action.