What does the term greenhouse effect mean in regard to earth's atmosphere

The greenhouse effect is a natural process that warms the Earth's surface.

Explanation:

Solar radiation heats Earth surface. When solar radiation reaches to Earth a certain level of radiation is being absorbed by Earth and rest of the radiation is being reflected to space. But because of greenhouse gasses (such as water vapour, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons) that exist in Earth atmosphere reflected radiation is being absorbed by atmosphere. If greenhouse gasses percentages raises into Earth atmosphere, the more radiation will be absorbed. Therefore, heat level of Earth is going to be raised.