black market

black babies

Third-world charities, the missions.

black day

A day of great disaster, misfortune or unhappiness.

black gold

Raw petroleum; crude oil.

black hat

A villain in a story, especially in a Western (a film or other work of the Western genre).

black mark

Something that negatively affects someone's reputation.

black out

To censor or cover up by writing over with black ink.

black over Bill's mother's

Describing rain-bearing dark clouds on the horizon.

black oxide

Any of several coatings for steels or copper; some are oxides (mainly iron(II,III) oxide), some are nitrites or nitrates, and some are selenides; all are black; the main purposes are the antireflective and cosmetic effects; the anticorrosion effects are small.