A stroke is a similar blockage in an artery that supplies blood to the brain. When a clot forms in one of those arteries and stops blood flow, a section of the brain begins to die. Stroke symptoms often don't include any pain or discomfort, and are more likely associated with losing feeling or the ability to move. Much of the time, strokes affect only one side of the body.
These two terms are so often misunderstood that some in the medical community are attempting to do away with stroke and replace it with the term brain attack. Personally, I doubt it will change. (Besides how difficult it is to do away with a widely accepted medical term, "brain attack" just sounds like the title of a really bad movie.)