What term is used for a circular seal to prevent the escape of a substance?

The term "dichtring" refers to a specific type of seal that is designed to prevent the escape or leakage of substances, often used in mechanical systems where fluids or gases need to be contained. Typically, these rings are made from materials that offer resistance to the substances they seal against, ensuring tight closure in various applications, such as in pipes, engines, or hydraulic systems. The function of a dichtring is crucial in maintaining pressure and preventing contamination, which is why it is a commonly used term in technical contexts related to engineering and maintenance.

The other terms provided do not refer to sealing devices. "Passfläche" relates to a contact surface; "nomenclature" is a system of names used in a particular field; and "pflichtmäßig" translates to "mandatory," which does not pertain to sealing mechanisms.