Why is Bluetooth called Bluetooth?

The name came out of a 1990s collaboration between Ericsson, Intel, and Nokia to standardize short-range wireless links between devices. An Intel engineer, Jim Kardach, had been reading about Viking history and proposed Harald Bluetooth, the king who united the warring tribes of Denmark and brought Norway under his rule around the 970s, as a code name for a technology meant to unite communication standards. The nickname Bluetooth likely referred to a dead tooth that had turned dark, though this is a later inference from the Old Norse epithet.

It was never meant to be the final name. The consortium planned to launch as PAN, for Personal Area Networking, but a trademark search found the term already widely used, and the fallback name RadioWire could not be cleared in time. Bluetooth shipped as the public name in 1998 more or less by accident, and it stuck. The logo combines the Younger Futhark runes for H and B, Harald Bluetooth's initials, into a single bind rune, which is why it looks the way it does.

The technology itself operates in the 2.4 gigahertz band shared with Wi-Fi and microwave ovens, using frequency hopping to avoid interference, and it has gone through many versions, with Bluetooth Low Energy in particular enabling the fitness trackers, tags, and sensors that run for months on small batteries. The Bluetooth Special Interest Group now has tens of thousands of member companies, which makes a name chosen as a joke about a Viking king one of the more durable accidents in consumer technology.