Wherever used in this article, the following terms shall have the meanings indicated:
An industrial building built prior to January 1, 1949, and meeting one of the following:
Listed on the National Register of Historic Places, as maintained by the United States Department of Interior.
Eligible for listing on the local historic register, as established by the Pawtucket Historic District Commission.
Not worthy to be nominated to the register, but determined to be eligible for the program by the Pawtucket City Council.
A new residential unit created within an historic industrial mill building.
Conversion of an historic industrial mill building to create residential use by substantial rehabilitation.