What term is used to describe pressure that is greater than atmospheric pressure?

The term used to describe pressure that is greater than atmospheric pressure is positive pressure. Positive pressure indicates that the pressure of the system exceeds the standard atmospheric pressure, which is considered to be approximately 14.7 psi at sea level. This is a common terminology used in various fields, including HVAC, to indicate that a system is operating at pressures above what is typically experienced in the atmosphere.

In contrast, the other terms provided have specific meanings that relate to different pressure contexts. High-side refers specifically to the part of a refrigerant system that operates at higher pressures compared to the low-side, but it is not a general term for any pressure above atmospheric levels. Vacuum denotes a pressure that is less than atmospheric pressure, essentially indicating a partial vacuum state. Negative pressure similarly indicates a pressure that is below the atmospheric pressure, which is the opposite of what is being asked in this question.

Therefore, the appropriate term for pressure greater than atmospheric pressure is positive, as it succinctly describes the condition without relation to any specific component or state of vacuum.