From the computer world: What does the word "modem" abbreviate?

This common computer peripheral gets its name from a portmanteau, a word blended from the two primary functions it performs. In the early days of the internet, home computers needed to connect using the existing telephone network (Review). The problem was that computers communicate using digital signals (discrete on/off pulses of ones and zeros), while phone lines were designed to carry analog signals (the continuous, smooth waves of a human voice). The device needed to act as a translator between these two incompatible languages.

The first part of its job is "modulation." To send information out from your computer, the device modulates the digital data into an analog audio signal that can travel across the phone line. On the receiving end, it performs the opposite task, "demodulation," by taking the incoming analog signal and translating it back into the digital data your computer can understand. That iconic series of screeches and hisses you heard when connecting to dial-up was the audible sound of two modems negotiating the rules for this constant back-and-forth translation.

While the dial-up technology that made the name famous is now rare, the term has stuck. The cable or fiber box in your home is still called a modem because it performs the same fundamental role, just with different types of signals and infrastructure. It continues to modulate and demodulate data to bridge the gap between the vast external network and your personal devices.