cadre
A small core group of trained, trusted leaders in a group.
A cadre is a small group of trained, dedicated people who form the core of a larger organization. Think of them as the experienced backbone that holds everything together and helps it grow.
In a school science club, the cadre might be the handful of students who've been members for years, know how everything works, and help train new members. In a military unit, the cadre consists of experienced officers and sergeants who train recruits and maintain discipline. Revolutionary movements often start with a small cadre of committed leaders who then recruit and organize others to their cause.
A cadre provides the framework that allows an organization to function and expand. A cadre doesn't do all the work by themselves, but they set the example, teach others, and ensure the group stays focused on its mission.
When someone joins a cadre, they're usually chosen for their skill, experience, and commitment. Being part of a cadre means others are counting on you to know what you're doing and to help maintain standards.