In this subchapter:
(1) "Teacher" means a superintendent, principal, supervisor, classroom teacher, school counselor, or other full-time professional employee who is required to hold a certificate issued under Subchapter B or a nurse. The term does not include a person who is not entitled to a probationary, continuing, or term contract under Section 21.002, an existing contract, or district policy.
(2) "School district" means any public school district in this state.
(3) "Term contract" means any contract of employment for a fixed term between a school district and a teacher.