Strobe light
This type of light source, which is also known as a stroboscopic lamp, generates flashes of light (the duration of which is typically somewhere about 200 microseconds) at regular intervals. It has been put to use in the field of photography to create high-speed photographs of moving subjects that are impossible for the human eye to follow, such as a bullet flying through the air. Additionally, strobe lights have been utilized to capture many shots of a moving subject within a single frame. For instance, Gjon Mili's photographs of dancers make use of this technique (1904-1984).
Do you have a better definition? Share it in the comments.