20 C.F.R. § 416.302

Definitions.

        For the purpose of this subpart—

            Benefits
             means any payments made under the SSI program. SSI benefits also include any federally administered State supplementary payments.

            Claimant
             means the person who files an application for himself or herself or the person on whose behalf an application is filed.

            We
             or
            us
             means the Social Security Administration (SSA).

            You
             or
            your
             means the person who applies for benefits, the person for whom an application is filed or anyone who may consider applying for benefits.

Official source