(i) "educational partnership organization" means a board of cooperative educational services, a public or independent, non-profit institution of higher education, a cultural institution, or a private, non-profit organization with a proven record of success in intervening in low-performing schools, as determined by the commissioner, provided that such term shall not include a charter school;
(ii) "board of education" means the trustees or board of education of a school district, or, in the case of a city school district of a city having a population of one million or more, the chancellor of such city district;
(iii) "school district" means a common, union free, central, central high school or city school district, other than a special act school district as defined in section four thousand one of this chapter.
(iv) "superintendent of schools" means the superintendent of schools of a school district, and, in the case of a city school district of a city having a population of one million or more, a community superintendent and the chancellor of such city district when acting in the role of a superintendent of schools.