noun
cadre
KAH-dray/ˈkɑːdreɪ/
A small group of trained people forming the core of an organization.
The trained rescue cadre coordinates the work together.

Etymology
The connection is through a square picture frame: a frame became an image for the permanent organizing skeleton of a military unit. From that developed the sense of a trained core group.
In context
The cadre are the officers and sergeants who oversee the ROTC program.
More examples
- The organization relied on a small cadre of volunteers.
- A skilled cadre formed the core of the rescue unit.
- The movement built a cadre of dedicated organizers.
Forms
cadre · cadres