For purposes of this subtitle, the term “partnership” includes a syndicate, group, pool, joint venture, or other unincorporated organization through or by means of which any business, financial operation, or venture is carried on, and which is not, within the meaning of this title, a corporation or a trust or estate. Under regulations the Secretary may, at the election of all the members of an unincorporated organization, exclude such organization from the application of all or part of this subchapter, if it is availed of—
26 USC § 761(a)
None identified. Default scope is assumed to be the entire title.