MEDC - More Economically Developed Country -> Examples) UK, USA, France, Germany, Spain, China, Japan etc.
-> They tend to have a better economy, providing good quality services, they also have better quality goods like food etc. They export and import a lot too. They also have lower birth rates because they have contraception more widely available and women tend to work more than have large families. MEDC's have better health care as well. Better transport, health, working conditions, salaries, jobs, sanitation etc.
LEDC - Less Economically Developed Country -> Examples) Brazil, Chile, Peru (and other parts of south America), parts of Africa, places like Zambia, Zimbabwe, Bangladesh etc.
->They tend to have a worse economy than MEDC's. They also tend to have poverty as a current issue. They often have poor working conditions and salaries in work places which tend to be factories or farms. They also tend to have high birth rates because contraception isn't available for them. This encourages schemes like family planning schemes. The women tend to have jobs on farms if they live in rural areas as oppose to urban areas and they have large families. People in rural areas are more likely to die of disease because they have poor sanitation and health facilities. The health facilities are sometimes within 10 miles of a village and the people often have to walk because they don't have sufficient transport (this is a huge problem especially for pregnant women). Children also have to work as well. When they are old enough they go to urban areas to find work and send money back to their families because they don't make much money in rural areas.
Hope this helps.
Did it for Geography GCSE at school...