HAIR PINS and BOB PINS ？ 

Historically in the Egyptian era upper class women used a type of hair pin to prevent their hair from falling into their plates at meal time. In literature of the Elizabethan era reference is made to a type of metal hair clip that had the ability to pinch hair. In Japan the predecessor of hair pins is the Kanzashi. In contrast to a comb which was a tool for coming hair the Kanzashi acts as a type of a pin that holds the hair in a bundle. Similar bone Kanzashi have been excavated from the remains of the Jomon period. 
 
Pins are basically divided into open pins and closed pins. 
To be precise, U-shaped open pins are called hairpins, and closed pins are called bob pins or bobby pins. They are also called hair grips in the UK. 
 
The derivation of the word “bob” dates back to the 16th century when it referred to a horses tail being cut short. This eventually came to mean short hair in the 17th century. Another origin of the bob style comes from boy soldiers in England having their hair cut short to distinguish them from adults. This short style was called a bob and consequently when a similar style became very fashionable among women in the 1920s it was called the bob cut. Due to the huge popularity of the bob cut there was also a dramatic increase in production of hair pins. 
 
These came to be known as bob pins as they were used to hold this new “bob style” in place.