The mafia boss nickname ‘pezzo da novanta’ derives from oranges, not gun caliber.

Evidence

Even in the metaphor which describes the mafia boss as a pezzo da novanta, “ninety” refers not, as is usually assumed, to the caliber of a gun—but according to Rosario Mangiameli (quoted in Lupo 1984: 60, n. 107)—to a superior variety of oranges, ninety of which would suffice to fill a box. And oranges, like olives but unlike wheat, grow far from the latifundia in areas where property is more fragmented. — Diego Gambetta, The Sicilian Mafia The Business of…, 860

Categorization

• CANDY: A delightfully wrong assumption corrected — people assume a gun reference, it’s actually oranges. Fun party fact about mafia etymology.
• XREF: Connects to the reader’s Gambetta-inflected analysis: the fact that oranges grow far from the latifundia, in fragmented-property zones, supports Gambetta’s claim that the mafia flourished where property was more fragmented and protection demand arose.