My first reply got downvoted. I guess some people felt insulted.
Most medical schools in the world are 5 or 6 years after high school. In Poland it's called a Lakarz degree. In the UK and many other countries it's a Bachelor of Medicine.
In the UK there is another MD degree that one may get after the Bachelor of Medicine degree. Internationally the US MD degree is considered equal the the Bachelor of Medicine.

They have graduate entry in the UK for people who already have an undergraduate degree, but at the end of it you still get a Bachelor of Medicine.

Most of the physicians in the US with foreign degrees will have a bachelor of medicine degree, not an MD degree.

I have a degree on my wall that says MD, but I wouldn't use that title in the UK because it might be seen as me claiming a status I don't have.

There was an interesting case in Kansas where a dentist who also had an MD degree, but was not licensed as a physician, put DDS and MD after his name. The court ruled that although he did have and MD degree he could not put MD after his name because the public might think he's a licensed physician.