A word I learned in Basic Training.
cadre
n.
5Fr, a frame < It quadro < L quadrum, a square: see QUADRATE6
1 basic structure or framework
2 an operational unit, as of staff officers or other key personnel, around which an expanded organization can be built
3 a small, unified group organized to instruct or lead a larger group; nucleus
4 a member of a political, esp. Communist, cadre