What term describes something that is required by law or regulations?

The term that best describes something that is required by law or regulations is "pflichtmäßig." This word is derived from the German term "Pflicht," meaning "duty" or "obligation," and it essentially conveys the idea of being mandatory or compulsory. In a legal or regulatory context, when something is pflichtmäßig, it indicates that there is a binding requirement that must be fulfilled. This can apply to various scenarios, such as compliance with safety standards, environmental laws, or corporate governance rules.

"Passfläche," which could refer to a "pass area" or something similar, does not denote a legal obligation. "Nomenclature" refers to a system or set of names or terms used in a particular field but does not imply any legal requirement. "Triebwerkgondel," which translates to "engine nacelle," pertains specifically to a component of an aircraft and does not relate to legal or regulatory requirements. Thus, "pflichtmäßig" is the most fitting term in this context, as it directly ties to the idea of obligations enforced by laws or regulations.