A medical device is any tool or equipment used to diagnose, prevent, or treat diseases or medical conditions in humans. It works mainly through physical or mechanical means, not through chemical action like a drug.

An active medical device is a medical device that requires a source of energy (like electricity or batteries) to operate and is used to diagnose, monitor, or treat a patient.

An active medical device for diagnosis is a powered device used to detect or monitor diseases or health conditions in a patient.

An active medical device for therapy is a powered device used to treat or manage a disease or medical condition in a patient.