A device — or a circuit inside a chip — that takes several separate signals and sends them down one shared line, so that one connection can carry the work of many. At the far end, a matching device called a demultiplexer pulls the signals apart again. Engineers often shorten it to MUX in diagrams and speech. The trick it performs can happen in different ways: by giving each signal a tiny turn in rotation, thousands of times a second, or by giving each one its own frequency slot. A learner does not need the physics; the useful picture is a narrow gate that many people take turns walking through so quickly that everyone seems to pass at once. This is squarely a technical word — telecoms, computer hardware, broadcasting, digital electronics — and outside those rooms nobody says it. It also has a related use in broadcasting, where a multiplex is the bundle of TV or radio channels squeezed into one transmission. Note the spelling wobble: multiplexer and multiplexor both appear in real engineering documents, with -er more common in general writing and -or lingering in some hardware texts.

多工器（電子與通訊用語，常直接說 MUX）；把多路訊號合併到一條線上傳送，另一端用「解多工器」demultiplexer 還原。