Known as MMA (manual metal arc) welding, but often referred to as just Arc or Stick welding. An electric current is passed through a flux coated welding electrode to produce an arc between the electrode and metal to be joined.
Before the days of MIG welding, a stick welder was the only option other than gas welding. It still plays a big part in modern engineering, but is mainly used for repair jobs on site due to the small size and weight of modern MMA machines.