Partnership law in the United States of America does not exist at the Federal level. This means that partnership law is instead decided upon and created by each individual state. Partnership law in the states is primarily based on common law principles regarding the nature of partnerships, including types such as general partnerships and limited liability partnerships.
Partnership law in America is further defined by the presence of the Uniform Partnership Act, which was originally proposed at the beginning of the 20th century. As a Uniform Act, this Act need not be adopted by any state, but the intent was that each state would adopt this Act of partnership law in order to have a generally uniform set of partnership law statutes for the entirety of America.
Each state might modify the partnership law as described in the Uniform Partnership Act somewhat, but in general, the original Uniform Partnership Act forms the basis of partnership law for the United States of America.
Under this partnership law, a general partnership is defined as the most common and default form of a partnership, in which each partner has unlimited liability to the partnership. A general partnership is synonymous with a partnership under basic partnership law as well, as the alternate forms of partnership, such as a limited liability partnership or a limited partnership, are modifications of a basic, general partnership.
Thus, under most partnership law, a partnership without a definitive partnership agreement that changes the nature of the partnership would default to a general partnership.