At the time they were careful not to call it a blockade, as a legal term of art that is considered an act of war as well. I think they termed it (euphemistically) a “quarantine” didn’t they?
At the time it was called a quarantine.
A few years later, it was called The Cuban Missile Crisis.
In fact I have a black military hat stating Cuban Missile Crisis in big all caps letter stating. Then, in smaller letters under that, a statement, saying, *UNITED STATES NAVY AT WAR*.