Advance party refers to 1. A security element of an advance guard. It is sent out from, and precedes, the advance guard support on the march. It sends forward and is preceded by the advance guard point.
2. A group of unit representatives dispatched to a port area in advance of the main body for the purpose of identifying and supervising the shipside delivery of the unit’s equipment.
3. A group of unit representatives dispatched to a probable new site of operations in advance of the main body for the purpose of arranging for the unit and its equipment upon arrival.