A black market is economic activity that takes place outside government-sanctioned channels. Black market transactions usually occur “under the table” to let participants avoid government price controls or taxes Black market relate to transactions that are illegal. Rumour has it that after the abolition of slavery, markets were still held to sell slaves. As the goods being sold were primarily “black", they became known as “black markets". Black Market refers to an illegal sale, trade, or transaction of certain goods or services almost always in cash or trade as to not leave a paper trail, or to bypass regulations. For example, guns and ammunition are huge sellers on the black market. ... Another good example would be designer knock offs.