An embargo is when a country or organization stops buying or selling things with another country, usually because they don't agree with something that's happening there.
Imagine two friends who are close but have been arguing for a while. They might stop talking to each other for a bit, which means they're not communicating as much as usual. An embargo is kind of like that, but between countries and things like food or fuel instead of conversations. If country A stops trading with country B because of some disagreement, it's an embargo.
An order by the government prohibiting ships from leaving port.
