A business organization in which two or more persons carry on a business together.
Partners are each fully liable for all the debts of the enterprise but they also share the profits exclusively.
Many states have laws which regulate partnerships and may, for example, require some form of registration and allow partnership agreements.
Far more significant, many jurisdictions allow corporations to partnership together or in a combination with individuals. These permutations allow a savvy lawyer to tweak a business structure to fit the needs of a client.
One of the basic advantages of partnerships is that they tend to allow business losses to be deducted from personal income for tax purposes (see also limited partner).