cadet

Concise Oxford English Dictionary © 2008 Oxford University Press:
cadet/kəˈdet/

▶noun

• 1 a young trainee in the armed services or police.

  ■ a secondary school pupil who undergoes voluntary training in the armed services.

• 2 formal or archaic a younger son or daughter.

  ■ a junior branch of a family.

– derivatives
cadetship noun.

– origin C17: from Fr., from Gascon dial. capdet, a dimin. based on L. caput ‘head’.