What is the meaning of Black_belt?

The highest belt colour in various martial arts.

Someone who has attained the black belt in martial arts.

Great skill in any field.

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.

A geographic region where the residents are predominantly or exclusively African-American.

A roughly crescent-shaped geological formation of dark fertile soil in the Southern United States.

Source: wiktionary.org