As used in this part:

Assistant Secretary means the Assistant Secretary of Labor for Occupational Safety and Health or the person or persons to whom the Assistant Secretary delegates authority under TFA.

Business days means days other than Saturdays, Sundays, and Federal holidays.

Complainant means the person who filed a TFA complaint or on whose behalf a complaint was filed.

Employee means an individual presently or formerly working for, an individual applying to work for, or an individual whose employment could be affected by, another person.

IRS means the Internal Revenue Service of the United States Department of the Treasury.

OSHA means the Occupational Safety and Health Administration of the United States Department of Labor.

Person means an individual, partnership, company, corporation, association (incorporated or unincorporated), trust, or estate.

Respondent means the person named in the complaint who is alleged to have violated TFA.

Secretary means the Secretary of Labor.

TFA means section 1405(b) of the Taxpayer First Act (TFA), Public Law 116-25, 133 Stat. 981 (July 1, 2019) (codified at 26 U.S.C. 7623(d)).