The word "vanguard" refers to the leading part of an advancing group, especially in a military context, but it can also apply to any area where individuals are at the forefront of new developments or movements. Essentially, it denotes those who are pioneers or innovators in a particular field.
The term "vanguard" comes from the Middle French "avant-garde," which translates as "fore-guard." The word is composed of "avant" meaning "before" and "garde" meaning "guard." Its usage in English dates back to the late 14th century, originally used in a military context.