The Taxable Wage Base refers to the maximum amount of wages that can be used to compute social security contributions.
Treas. Reg. § 1.401(l)-2(d)
Additional Helpful Information
Contributions to qualified plans and SEP IRAs can be integrated with social security ( social security integration). The primary objective of this integration is to permit individuals, whose social security contributions are capped at the taxable wage base, to receive a larger contribution amount under the qualified plan or SEP IRA.