The name is expressed with affection by some, with hostility by others, but it calls up history for everyone.
The story of his life is very much the story of our times: revolutionary movements, the Cold War, East v West, North v South, communism v capitalism - except that most of the world has passed him by.
Fidel Castro has remained the same, a symbol of revolution, a communist who has survived the fall of communism.
Before surgery took him out of public view in July 2006, he inspired his followers with slogans and five-hour speeches.
Fidel's views continued to be made public though in the form of editorials and occasional TV appearances.
Fidel maintained his rule with an iron grip, sending opponents to prison for years.
Throughout his leadership, he railed against the US, its economic and trade embargo and against the evils of free markets
Fidel has been praised for standing up for the oppressed of Latin America, for opposing the Yankee imperialist, for making Cuba into a more equal society than many, for developing Cuba's health service and sending doctors abroad to help others.
And it wasn't only doctors he sent abroad. He despatched troops to Angola and Ethiopia in support of fellow revolutionaries. His hand was seen in many a revolutionary movement in his own continent.
But he has also been condemned for intolerance, for keeping his people poor and for refusing to see the benefits of economic liberalisation that even the communists of China have embraced.
Fidel Castro stopped his people from leaving the island, leading them to risk their lives in rickety boats to try to get out.
At one stage in the early years of the Reagan administration he was accused of trying to take over Central America for the Soviet Union by revolution.
Washington at that time saw a path that led from the guerrillas of El Salvador through Nicaragua to Cuba and right up to the door of the Kremlin.
Cuban assistance to the small and then revolutionary island of Grenada in the Caribbean prompted a full-scale US invasion.
Throughout his rule, President Castro remained in almost permanent confrontation with the United States - and it with him.
The American embargo on Cuba has been used by both sides - as a policy by the US to isolate Cuba and as an excuse by Fidel Castro for the island's poverty.
US President Barack Obama and Castro's successor as president, younger brother Raul, announced a thawing in relations in 2015 but the embargo remains in place.
When Mr Obama visited earlier this year - the first by a US leader in more than half a century - Castro remained defiant, saying Cuba did not need any gifts from the "empire" in a damning letter.
He cut a giant figure on the world stage during the 47 years he controlled Cuba - at one point bringing the US and the Soviet Union to the brink of nuclear war.
It was the Cuban missile crisis of 1962 that propelled him into worldwide prominence.
Before that he had been just a glamorous revolutionary leader. He had overthrown the dictator Batista in a classic guerrilla war and had fought off an American-led invasion by Cuban exiles on the Bay of Pigs in 1961.
But when Nikita Khrushchev decided, with Fidel Castro's agreement, to station nuclear missiles in Cuba itself, the island leader turned from being a thorn in the side of the Americans into being a mortal threat.
It was only the skilled diplomacy of Jack Kennedy (and of Khrushchev in the end) that saved the day, and Fidel's own island from destruction.
The then-US defence Secretary Robert McNamara met President Castro in 1992. He said the Cuban leader told him there were 162 nuclear missiles in Cuba at the time of the crisis.
He asked Castro if he had recommended they be used. The answer was:
"Yes, I did."
"And what would have happened to Cuba?" Mr McNamara asked him.
"It would have been destroyed."
Fidel Castro was not part of the diplomacy that ended the missile crisis.
But he came out of the crisis remarkably strengthened. Kennedy promised that the US would not invade Cuba, a promise that has held.
The CIA made efforts to get rid of him with bizarre plots involving the Mafia and poison. They came to nothing. President Castro's people took immense precautions to protect him from potential harm from food and drink, as diplomats who invite him to their receptions in Havana found out.
He survived harm from his enemies.
And whatever happens to Cuba after him, the name of Fidel will survive in history.
He is instantly recognisable both from his appearance - the beard and the military fatigues - and from his first name alone: Fidel.