3Weg

3weg is a German-language term meaning "three-way," used as a general descriptor for configurations, devices, or routes that involve three possible paths, ports, or connections. The term is commonly written as 3-Wege, 3-Weg, or 3weg in technical contexts, and derives from the German words drei and Weg.

The word functions as a flexible label across several disciplines. In electronics and mechanical systems, 3weg denotes components that connect or route signals, fluids, or power among three ports or paths, rather than limiting itself to a single input/output pair. In practice, this often refers to devices designed to switch, mix, or divert flow or signals among three options.

In plumbing and HVAC, three-way valves (dreihweg-ventile) are a typical example, directing a fluid between two paths or mixing flows from multiple sources. Such valves are used in heating circuits, cooling systems, and industrial processes to adjust direction or proportion of flow without introducing additional equipment.

In computer networking, the term appears in the concept of a three-way handshake, which describes the initialization sequence used by TCP to establish a connection between two endpoints. The sequence typically involves a series of three messages (SYN, SYN-ACK, ACK) to synchronize both sides before data transfer begins.

In traffic engineering, a three-way intersection or three-way junction describes a crossroads where three roads meet, requiring specific signaling or right-of-way rules to manage traffic flow.

Overall, 3weg is a descriptive label rather than a proper noun, used to indicate triadic configurations across multiple technical fields.