Big Ben is not the official name of the clock, which is actually the Great Bell of Westminster. The name Big Ben is thought to have originated in the mid-19th century, when the bell was named after Sir Benjamin Hall, the First Commissioner of Works at the time the bell was cast.
Here are some other nicknames for Big Ben:
* The Great Bell of Westminster
* Big Ben Clock
* The Westminster Chimes
* The London Bell
* The Parliament Bell
* The Tower Clock
* The Queen's Clock