Supplemental air refers to additional air supply or ventilation used to enhance existing airflow. In the domain of heating, ventilation, and air conditioning (HVAC) systems, there are several synonyms for supplemental air. One synonymous term is "auxiliary air", which denotes the extra air supplied to support the existing airflow. Another synonym is "complementary air", which signifies the additional supply of air that works alongside the primary airflow. "Extra air" is another term used to describe the supplementary air provided to improve ventilation. These synonyms all convey the concept of supplying extra or supplementary air to enhance existing systems, promoting better air circulation and ventilation in various environments.