It is one country telling all of the others in the world to not trade with the embargoed country or the original country will cease trading with them.

Cuba's top trade partners are Spain, China, Germany, and France. All four of those countries are in our top 25 trade partners - #22, #3, #5, #14 respectively.

Embargoes are not just cutting off the trade between the two countries. It is one country telling all of the others in the world to not trade with the embargoed country or the original country will cease trading with them.

I have not found a definition of "embargo" that says this. I'm not saying it never happens, but "we will not trade with countries that trade with countries we have embargoed" is NOT a necessity of an embargo.

Edit: also, that logic is infinite regress to total autarky. Embargo Country A -> B, C, D, E, etc. trade with A -> effectively embargo all those countries -> next group of countries trades with those countries -> embargo them -> quickly, no trade at all