The Vacuum Terminology You Should Know Introduction: Vacuum terminology has evolved over time. In order to describe what you are looking for, it is helpful to have a guide that describes what different terms mean so people from different industries can communicate with one another. We’ll start from the beginning and focus on vacuum measurement and control. The term vacuum gauge has a meaning when talking with people in the scientific and industrial vacuum communities, and another meaning in the MRO market (Maintenance, Repair and Operations, such as HVAC). In MRO, people are typically referring to fairly inexpensive all in