Translated from Spanish, it means "silver or lead". For someone unlucky enough to be presented with the expression, it usually means they face an unpalatable choice to either take a bribe or a bullet.
For many years now, the bribe and the bullet have become the standard modus operandi of Mexico's notorious drug mafias, the two most powerful of which are the Los Zetas and Sinaloa cartels. In any short article such as this, it is impossible to give any real sense of the fear, violence, political power and massive illegal profits generated by these cartels.
Such is the extent of their presence both in Mexico and across Central America and now, increasingly, in the United States itself, that law enforcement and counter-terrorism analysts admit they have long since ceased to resemble traditional gangs.
Their activities have instead become insurgencies in their own right, the impact and influence of which the likes of al Qaeda or the Taliban could never hope to match.
Across Mexico, Los Zetas and Sinaloa now control huge swathes of territory, including large cities such as Ciudad Juarez. There they have countless politicians, police, and judges on their payroll. The fate that befalls anyone opposing them is horrendous. Without exception they will be shot, blown up, tortured, decapitated, or become a victim of "El Guiso"– the stew – where the captive is placed into a 55-gallon drum filled with diesel before it is set alight.
Only last month the torsos, severed heads and hands of 43 men and six women were found piled by the side of a road near Monterrey. Said to be behind their murder was the Los Zetas cartel henchman Daniel Elizondo, nicknamed "El Loco", who was keen to send out a message in a turf war over who controlled this drug smuggling route near the US border.
Faced with these levels of intimidation, police officers in many areas of Mexico have simply stopped doing their job – and God help any journalist who pokes an investigative nose into cartel business.
I mention all of this to give some idea of the challenges now facing Mexico's president-elect, Enrique Pena Nieto, fresh from his election victory last weekend. It's a measure of just how much corruption is perceived to have penetrated every aspect of Mexican society that yesterday, Mexico's Federal Electoral Institute decided to recount more than half the ballot boxes used in the presidential election after finding inconsistencies in the vote tallies.
With 99% of the vote tallied in the preliminary count, Mr Pena Nieto of the Institutional Revolutionary Party (PRI) led with 38% of the vote, while opponent Andres Lopez Obrador of the Democratic Revolution Party had 32%.
Mr Lopez Obrador has refused to accept the preliminary vote tallies, saying the election campaign was marred by overspending, vote-buying and favourable treatment of Mr Pena Nieto by Mexico's semi-monopolised television industry. But other more dangerous players too have doubtless cast a shadow over the polls.
While few believe the cartels can substantially influence or steer the leading presidential candidates, at the state and municipal level it's a different story.
"At the regional level, they [narcos] either buy candidates or impose them directly by working within the internal campaigns of political parties," was how one senior public security official in Mexico City summed it up. "When this isn't sufficient, they threaten voters and electoral functionaries directly."
According to the US Department of Justice, Mexico's "narcos" are thought to earn between $18bn and $39bn annually from the North American franchise alone of their illicit cocaine, methamphetamine and heroin trafficking over the border. Add to this the profits from extortion, people trafficking and other contraband and you have the kind of money that easily buys favours in high places.
It also ensures an army of hitmen, assassins and neighbourhood footsoldiers are equipped with weapons and technology that are state-of-the-art, be it assault rifles, rocket launchers, satellite communications or the parts needed to build improvised submarines able to ferry drugs along coastlines.
Watching all of this in the wake of Mexico's presidential elections is a nervous US administration and security apparatus.
With Mr Pena Nieto due to take up his presidential role in December, Washington will no doubt be closely monitoring a politician whose PRI party ruled Mexico for most of the twentieth century until 2000 – a time during which the cartels' power soared amid widespread corruption and weak institutions.
Mr Pena Nieto's remarks over the past few days that he hopes to prioritise violence reduction over battling the cartels has done little to calm an outbreak of security jitters among his North American neighbours.
Many in the US State Department, the country's Drug Enforcement Administration (DEA) and at CIA headquarters at Langley are already wondering whether Mr Pena Nieto's election might be the start of a Mexican presidency tempted to cut deals with its mafia to reduce violence in exchange for turning a blind eye to drug shipments or cracking down on cartel kingpins.
US fears are understandable, for unlike American mafia gangs, Los Zetas – the most violent and powerful of the Mexican cartels – has with its unlimited funds and unlimited access to weaponry the capacity to wreak criminal havoc on US soil.
The FBI estimates Los Zetas has already penetrated hundreds of US cities by using local criminal gangs as proxies, and it is likely it has links with listed terrorist organisations.
Also at the Zetas' disposal in their stronghold in north-eastern Mexico are the most sought-after smuggling routes into the US. All this enables them to peddle drugs you can buy for one peso in Mexico and sell them for $100 across the border, according to Jeffrey Prather, a former DEA special agent.
As Mexico concludes its partial recount of ballots from Sunday's election, the bribe and the bullet will continue to be the cartels' weapons of choice. Frankly, it's hard to see how president-elect Pena Nieto's proposed shift in strategy will do much to disarm the narcos for the foreseeable future.