The word for today is…
cadre (noun):
1: a nucleus or core group especially of trained personnel able to assume control and to train others
2: a cell of indoctrinated leaders active in promoting the interests of a revolutionary party
3: a member of a cadre
4: frame, framework
Source : Merriam -Webster
Etymology : Huey Lewis once sang that “it’s hip to be square.” A This prompts us to ponder an etymological descendent (via French and Italian) of the Latin word for square, quadrum: cadre. Squares being a logical and standard shape for frames (as of window and picture varieties), it’s easy to understand why French speakers and later English speakers adopted cadre as a word meaning “frame.” A sense of cadre referring to a metaphorical framework for something (such as a novel or curriculum) soon developed. And if you consider a group of officers in a military regiment as the framework that holds things together for the unit, you’ll understand how yet another sense of cadre, referring to a nucleus of trained personnel, arose. Military leaders and their troops are well-trained and work together as a unified team, which may explain why cadre is now sometimes used more generally to refer to any group of people who have some kind of unifying characteristic—such as a belief in the heart of rock and roll, or perhaps the power of love.