black belt

noun6

1. •
   The highest belt colour in various martial arts.
2. •
   Someone who has attained the black belt in martial arts.

   • Raymond is a black belt in karate.
3. •
   A senior manager who is expert in one of various management systems such as Six Sigma or DMAIC and acts in a project leader or mentor role.

   • I had the good fortune of being engaged to participate as a trainer to GE Capital Corporation, where we helped to launch their now well-known and highly regarded black belt program. — 2011
4. •
   (US) A geographic region where the residents are predominantly or exclusively African-American.

   • Bernard Cosman found that in Georgia, it was the black belt whites who gave Goldwater his largest percentage of the vote. — 1992
5. •
   (informal, figurative) Great skill in any field.
6. •
   A roughly crescent-shaped geological formation of dark fertile soil in the Southern United States.