IPA: //ˈmʌltɪˌplɛksər//
KK: /mʌlˈtɪplɛksər/
A device that takes multiple input signals and combines them into one output signal, often used in electronics and telecommunications.
The engineer used a multiplexer to send multiple data streams over a single channel.
Multiplexer → It is formed from "multi-" (meaning many) and "plex" (from Latin "plicare", meaning to fold). The word "multiplexer" refers to a device that folds or combines many signals into one for transmission.
Think of 'many' ('multi-') signals being 'folded' together ('plex') into one, which is what a multiplexer does.
No commonly confused words.