What is the meaning of the last name Gilbert?

The last name Gilbert is of Old French and Germanic origin, derived from the given name "Gilbert," which means "bright pledge" or "shining promise." It combines the elements "gisil," meaning pledge or hostage, and "berht," meaning bright or famous. The name became popular in England after the Norman Conquest and has various spellings and forms across different cultures. It is often associated with nobility and historical significance.