Answer
The term "Bluetooth" originates from Old Norse, where it was known as "Blátǫnn," meaning "blue tooth" or "dark tooth." King Harald Bluetooth Gormsson of Denmark, who reigned in the 10th century, was known for his bad tooth that gave him a bluish-black appearance. The name "Bluetooth" was chosen for the wireless technology as a tribute to the king's pivotal role in uniting Denmark and Norway.