Farming means raising food or animals, usually to sell. A farm is usually a large piece of land used for raising food and/or animals and the farmer is the person who does this work. The verb farm out means to pay someone else to do some of your work.
Before mechanization made farming easier, farms were small family owned plots of land. Farmers grew food and raised animals to feed his own family and to sell locally.
Marvin owns a large house painting business, and he only takes the bigger jobs for himself. He farms out the smaller jobs to a smaller company in town.
Other types of farming have arisen in recent years. Fish farming has become widespread, especially for salmon and trout. The number of wind farms has increased around the world. They are made of rows of wind turbines that use wind to generate electricity. Some of the sunnier states in the United States have solar farms where dozens or hundreds of solar panels are creating electricity by storing energy from the sun.
Although wind farms have become more widespread, not everyone is in favor of their existence. People who live near them complain of a variety of physical ailments.