(intransitive) To participate in a black market. / (transitive) To sell in a black market.

A penalty card issued by an official in several sports for infractions. / (fencing) The most severe of penalties, which results in the fencer being expelled from the match.

trade that is in violation of restrictions, rationing, or price controls / the people who engage in such trade (considered as a group), or that sector of the economy

(idiomatic) Explicitly, in writing, clearly and without doubt or misunderstanding, without any grey areas. / (literally) Using shades of gray rather than color.

(film) To end a film or a scene of a film by causing the image to be gradually dimmed into black.

(film) An ending of this kind.

(chemistry) A form of carbon black formed by the decomposition (but not by the burning) of acetylene. It is characterized by its high degree of crystalline orientation compared with other sources of carbon black.

plural of Black Friday

An omnivorous slug found in Europe and the Pacific Northwest, Arion ater, not always black, despite the name.

(philately) The world's first official postage stamp, issued in 1840 in the United Kingdom as part of postal reforms.