My lady friend has coronary artery disease. She was too embarassed to tell me any more. Can you explain it to me please?

Heart disease. The blood supply to the heart is from the "coronary arteries" which branch off the aorta, the main artery leaving the heart. When someone has coronary artery disease these arteries have "plaque' build-up , usually from elevated cholesterol, leading to decreased blood flow to the heart muscle. This can lead to a "heart attack" where the blockage causes the heart muscle to die.
Blockage in arteries. The coronary arteries are blood vessels that supply the heart muscle with oxygen and nutrition. When they get plugged by cholesterol and/or a blood clot a heart attack occurs. When the blockage is not complete, but restricts the blood flow to the muscle, various activities like vigorous exercise can cause chest symptoms (angina). I hope your friend is getting medical care for her condition.
Clogged arteries. Coronary artery disease mostly means clogged coronary arteries. Coronary arteries are the arteries surrounding the heart and give blood supply to the heart muscle. Coronary artery disease may lead to a heart attack and significant disability or death. Those who have coronary artery disease need to consult cardiologists.