A society is generally thought of as a group of individuals (usually humans, but sometimes other animals such as bees and ants) that live and interact with each other on a regular basis. Human societies are usually formed for social, industrial, economic and other purposes.
In a society, the individual members are generally free to achieve their own aims which they would not be able to attain on their own, outside of the society or social group. At the same time, societies themselves are unique and are not dependent on the individuals that comprise them for their identity; that is, the whole (the society) is greater than the sum of its parts (the individuals that make up the society). Consequently, societies tend to outlive their individual members.
Individuals in a society tend to share common values and goals, which is usually what brings the individuals together in the first place. Although the individuals in a society usually interact with each other, individuals may interact with others outside of the society and still remain a part of the society.
One of the advantages to living in society is that in times of need, socities will come together to help individuals requiring aid. For example, after Hurricane Katrina damaged several areas along the Gulf Coast of the United States, countless organizations and individuals came out to offer help, both physical aid (for recovery and reconstruction) and material aid (money and donated items such as food and clothing).
Just as societies assist those members who are in need, they can also reward members whose behavior they approve of, and punish those individuals they disapprove of. Soldiers who fight bravely are rewarded with medals, while those who violate the norms of a society can be ridiculed, exiled or even imprisoned and/or executed. Thus societies evolve and survive, ensuring they maintain the traditions and values that make them unique.