What is the name of the device used to blow-dry hair?

The device used to blow-dry hair is a hair dryer, also called a blow dryer.

A typical hair dryer combines a fan with an electric heating element. The fan moves air across the heated element and directs the warm airflow through a nozzle. This speeds evaporation of water from the hair and also helps shape it while it dries.

The earliest hair dryers were large salon machines. In 1888, French stylist Alexandre-Ferdinand Godefroy created a seated dryer connected to a bonnet. Handheld models appeared around 1920, although early versions were heavy, relatively weak, and raised safety concerns. Modern dryers are lighter and may offer multiple heat and speed settings.

A diffuser is an attachment for a hair dryer, especially useful for curly hair because it spreads the airflow and reduces disturbance. A flat iron straightens hair with heated plates, while a curling iron shapes it around a heated barrel. None of those tools is the general device meant by “blow-dry.”