The definition of a Pack Unit AC is a type of air conditioner that can be used to cool a single room or space. It is a self-contained unit that is typically wall-mounted and is designed to provide cooling for a single room or area. Pack Unit ACs are a popular choice for residential and commercial applications due to their low cost and convenience. Pack Unit ACs can be used to provide cooling in the summer months and can help reduce energy consumption compared to other types of air conditioners. Pack Unit ACs are composed of a fan, evaporator coil, and a condenser coil, all working together to cool a room or area. The fan draws air through the evaporator coil, which is cooled by the refrigerant and then blown out of the unit. The condenser coil then releases the heat from the refrigerant to the outside air. Pack Unit ACs are efficient, easy to install, and provide an economical way to cool a single room or area.