A Chinese gang or triad.

plural of black society

A type of extortion racket, typically involving sending a letter demanding that the victim leave a sum of money in an agreed location to avert a threatened kidnap, arson, murder, etc.

Clipping of black rhinoceros.

Alternative letter-case form of Black Power

A structure that is embedded in a uniformly bright aurora, where its optical emission is significantly reduced, presenting as either patches or arcs that mainly drift eastwards.

plural of black aurora Alternative form of black auroras

plural of black aurora Alternative form of black aurorae

A leaf spot disease of banana plants, caused by the ascomycete fungus Mycosphaerella fijiensis (anamorph: Pseudocercospora fijiensis).

(geology, oceanography) A kind of hydrothermal vent found on the seabed, emitting clouds of black material. / Used other than figuratively or idiomatically: see black, smoker.