The low energy functionality of Bluetooth is built on a new development framework using Generic Attributes, or GATT. This makes it flexible for developers and it can be used for just about any scenario.
Common applications for Bluetooth include connecting mobile devices to ancillary devices such as headphones or speakers.
Many smartwatches use Bluetooth to pair with a smartphone, since few smartwatches can connect directly to cellular networks themselves. For example, the Apple Watch will use Bluetooth when the paired iPhone is nearby, saving power. If Bluetooth is not available, the Apple Watch will use wi-fi.
Bluetooth is expected to be a key technology for connecting the Internet of Things in coming years.
Bluetooth is named after the 10th century Danish King Harald Blåtand or Harold Bluetooth in English. This is because Bluetooth was designed to unify disparate devices and products, and Blatand unified warring factions in parts of Scandinavia.