26 U.S.C. § 1313 — Definitions

(a) Determination. For this part, “determination” means: (1) a final Tax Court decision or a final judgment, decree, or other order of a court with proper jurisdiction; (2) a closing agreement under section 7121; (3) the Secretary’s final disposition of a refund claim. For items allowed, the claim is finally disposed of on the date the refund or credit is allowed, or on the date notice is mailed that the claim is disallowed because of offsetting items. For items disallowed wholly or partly, or items the Secretary applies to reduce the refund or credit, it is finally disposed of when the time to sue about those items expires, unless a suit is filed before then; or (4) under the Secretary’s regulations, an agreement for this part, signed by the Secretary and a person, concerning that person’s tax liability under this subtitle for a taxable period, or the liability of the person for whom that person acts. (b) Taxpayer. Despite section 7701(a)(14), “taxpayer” means any person subject to a tax under the applicable revenue law. This section does not define “applicable revenue law.” (c) Related taxpayer. For this part, “related taxpayer” means a taxpayer who, during the taxable year in which the erroneous inclusion, exclusion, omission, allowance, or disallowance occurred, had one of these relationships with the taxpayer for whom the determination is made: (1) husband and wife; (2) grantor and fiduciary; (3) grantor and beneficiary; (4) fiduciary and beneficiary, legatee, or heir; (5) decedent and the decedent’s estate; (6) partner; or (7) member of an affiliated corporate group, as defined in section 1504.