For the purpose of this article, the following terms shall have the respective meanings ascribed by this section:

(1) EMPLOYEE. Employee as defined in the Internal Revenue Code, as amended from time to time.

(2) EMPLOYER. Employer as defined in the Internal Revenue Code, as amended from time to time. An employer is required to withhold tax from the wages of employees to the extent that such wages are earned in Alabama, whether the employee is a resident or a nonresident of the state.

(3) INTERNAL REVENUE CODE. The Internal Revenue Code of the United States, as amended from time to time.

(4) PROVISIONAL CONSTRUCTION EMPLOYERS. A provisional construction employer is any employer, including members of its affiliated group as that term is defined in the Internal Revenue Code, that (i) employs 50 or more employees in a construction project for qualified property located in a tax increment district in which not less than 50 percent, by area, of the real property within the tax increment district is an enhanced use lease area, as these terms are defined in Section 40-9E-1, a construction project for a qualifying industrial or research enterprise described in Section 40-9B-3(a)(8)e., or a construction project, the cost of which is part of a qualifying entity's capital cost, as these terms are defined in Section 40-9D-3, and (ii) has not registered in the tax year preceding the current tax year with the Alabama Department of Revenue for withholding tax purposes. If the provisional construction employer reports and pays all past withholding taxes due the state and continues to report and pay for a one-year period all withholding taxes due to Alabama, the employer will no longer be deemed to be a provisional construction employer.

(5) WAGES. Wages as defined in the Internal Revenue Code, as amended from time to time. However, Alabama does differentiate from federal requirements for certain classes and amounts pursuant to departmental rules adopted via the procedures in Title 41.