For purposes of this title, the term “Roth IRA” means an individual retirement plan (as defined in section 7701(a)(37)) which is designated (in such manner as the Secretary may prescribe) at the time of establishment of the plan as a Roth IRA. Such designation shall be made in such manner as the Secretary may prescribe.
26 USC § 408A(b)
None identified. Default scope is assumed to be the entire title.