A vent, or outlet, is an opening that allows air, gas, or liquid to flow in or out of a space. Vents are commonly used in buildings for ventilation, helping to maintain indoor air quality by removing stale air and bringing in fresh air. They can also be found in appliances, such as heaters and air conditioners, to facilitate the circulation of air. In addition to their role in ventilation, vents can also serve as drainage points for excess water or other fluids. For example, plumbing systems often include vents to prevent pressure buildup and ensure proper drainage. Overall, vents are essential for maintaining a safe and comfortable environment.