Bluetooth is a standard for short-range wireless communication between various electronic devices including keyboards, computers, laptops, PDAs, smartphones, and many others. ¹⁾

Bluetooth got its name from a Danish king. Harold 'Blåtand' Gormsson, the 10th century King of Denmark, enjoyed blueberries so much that his teeth were permanently stained blue. The “Bluetooth” version of his username is clearly anglicized. ²⁾