The Farm is a building in Age of Empires that provides a reliable supply of food, which can only be gathered by Villagers. The Market must be built in order to build Farms. Unupgraded farms provide 250 food.
Although multiple villagers can gather from a farm at once, secondary villagers cannot gather food until the original farmer leaves to deposit food. Farms do not allow units (even the villager) to pass through it (meaning you have to be careful about their placement). They cannot be automatically reseeded.