Section 402A of the tax code established the ability for employers to have Roth accounts in employer's qualified retirement plans (401(k), 403(b) and governmental 457(b) plans as well as the federal TSP plan), similar to but not the same as a Roth IRA, should the employer's plan choose to adopt such provisions.
Roth IRAs were created under a different section of the tax code, section 408A. The only tie between a designated Roth account in an employer's qualified retirement plan and a Roth IRA is that, under certain circumstances, money in a designated Roth account in an employer's qualified retirement plan is permitted to be rolled over to a Roth IRA.
