A more thorough explanation:

Definition: Patent infringement is when someone violates the rights of a person who owns a patent for an invention. This means that unless the patent owner gives permission, it is illegal to make, use, offer to sell, or sell something that has every part of a patented claim or something that is very similar to it while the patent is still valid. For infringement to happen, the act must be done in the United States or the product must be imported into the United States after being made in another country.

Example: Let's say that John invents a new type of phone charger and gets a patent for it. If Sarah starts making and selling phone chargers that are exactly like John's without his permission, she is committing patent infringement. This is because she is using every part of John's invention without his permission.

Another example: If a company in China makes a product that is very similar to a patented product in the United States and then sells it in the United States, they are committing patent infringement. This is because they are importing a product that is very similar to a patented product without the permission of the patent owner.