mano nera \man'-o ner'-a\ n. Italian, lit. black hand. 1.a gang that originated in central Italy in the Abruzzi Region in late 1800 and early 1900. Mano Nera is not to be considered the same as Cosa Nostra (our thing) that originated in Sicily. The gang's activity was extortion. Their calling card was a single left-handed glove left on the door step of the person who did not pay. Popular writers who claim that the calling card was the black hand stamp do not have first hand source of the actual calling card.
"If you do not pay the extortion money to the mano nera, you may find a single black left-handed glove on your doorstep. Then you better look out!" Luigi said to Giovanni