A social unit of people that is structured and managed to meet a need or to pursue collective goals.
All organisations have a management structure that determines relationships between the different activities and the members, and subdivides and assigns roles, responsibilities, and authority to carry out different tasks.
Organisations are open systems--they affect and are affected by their environment.
Read more: http://www.businessdictionary.com/definition/organizatio n.html#ixzz3CAXmvErf