As used in this subchapter:
(1) “Contractor” means any person who contracts orally or in writing directly with a person holding an interest in real estate, or such person's agent, for the construction of any improvement to or repair of real estate;
(2) “Material supplier” means any person who supplies materials, goods, fixtures, or any other tangible item to the contractor or a subcontractor, or an individual having direct contractual privity with such persons;
(3) “Person” includes an individual, a partnership, a corporation, a limited liability organization, a trust, or any other business entity recognized by law; and
(4) “Subcontractor” means any person who supplies labor or services pursuant to a contract with the contractor, or to a person in direct privity of contract with such person.