In the US medic and paramedic are sometimes used interchangeably for the people who work on ambulances doing advanced life support. A step below them in training are the EMTs, or emergency medical technicians. At least in my state, EMTs provide basic life support and are sometimes assisted by a paramedic unit for more serious emergencies. EMTs can administer oxygen and use defibrillators. Paramedics have significantly more training and can start IVs and administer other medications after getting orders from a doctor. I've also heard the word medic used as a synonym for doctor, particularly in a military context. Nurse provide the majority of patient care and usually work in a doctor's office or hospital. They have more training than paramedics.

Nurses are assistants to doctors and/or they take care of patients staying at a hospital. To be a nurse you need an undergraduate degree, but to become a doctor you need to do postgraduate study. Traditionally, doctors were men and nurses were women, but this distinction no longer applies. The overwhelming majority of nurses ARE still female, but there are male nurses. I think the proportion of male and female doctors are essentially the same nowadays. A medic is a doctor in the military. Their job is to treat injured soldiers. A paramedic is someone whose job is to treat the injured at the scene of the accident. If you get into a car crash, paramedics might arrive and try to help you. If you're badly injured the paramedics might ride with you in an ambulance, trying to help you while driving. When you arrive at the hospital the paramedics hand you over to the doctors who work there. I'm not sure if paramedics are technically doctors or not.

someone whose job is to look after people who are ill or injured, USUALLY IN A HOSPITAL!

Medic: a medical doctor , Paramedic is :someone who has been trained to treat sick or injured people, especially at the scene of an accident.