What does the term heat syncope mean?

Overheats and faints. A person who gets overheated will automatically dilate (widen) the blood vessels in his skin so that more blood will flow to the skin. His body does this in hopes of cooling him down, just like the elephant who sends more blood to his ears to cool his body down. The person, however, feels lightheaded and may faint because there is not enough blood flowing his brain (too much blood is in the skin).
Heat exhaustion. Any person having syncope while exposed to the sun or warm temperatures. This is associated to the vasodilation, to the perspiration o lack of perspiration, associated to dehydration, fasting, or to exertion. If severe could cause signs of stroke then called heat-stroke.