(euphemistic) depression, melancholy / Used other than figuratively or idiomatically: see black, dog.

An illicit drug formed from the incomplete acetylation of morphine, containing a variable percentage of heroin.

(rare) plural of black drink

A tea-like drink made by Native Americans, and then by others, having exhilarant and diuretic properties. It is thought to have been brewed with Ilex vomitoria (yaupon) or Ilex cassine leaves.

plural of black bloc

Black Peter.

Technical silence. Noise that has a frequency spectrum of predominantly zero power level over all frequencies except for a few narrow bands or spikes.

(Australia) An aborigine from the remote outback.

(music) Any of the notes (flats and sharps) produced by the black keys on a piano or similar keyed instrument.

plural of black-jack