It comes from the Latin word "ambulare," which means "to walk about."
Here are some examples of words that use the root "ambul":
* Ambulate: To walk or move about.
* Ambulance: A vehicle designed to transport sick or injured people.
* Ambulatory: Able to walk or move about.
* Somnambulism: Sleepwalking.
* Perambulator: A baby carriage.