A branch that terminates at a developed length of 2 feet or more by means of a plug, cap, or flange is considered a...

A branch that terminates at a developed length of 2 feet or more by means of a plug, cap, or flange is classified as a dead end. This term is used in plumbing to describe a section of piping that does not allow flow to continue beyond the termination point, effectively making it inactive for the passage of water or waste. Dead ends can sometimes pose problems, such as stagnation of water, which can lead to issues like bacterial growth or corrosion, making identification of such sections crucial for proper plumbing maintenance and design.

In contrast, an open line would be one that continues to allow for the flow of substance beyond its termination point, hence not fitting the criteria set forth in this question. A service line typically refers to the portion of the plumbing system that delivers water or other services to a building, which again does not match the definition of a terminated branch. Lastly, a branch line usually indicates a section of piping that connects to a main line to deliver fluid to different fixtures or areas, but does not inherently imply that it is terminated with a plug, cap, or flange as described.