As used in this act:

(a) The words “school district” mean and include any common-school district, rural high-school district, community high-school district, and any first- or second-class city school district; and

(b) the words “governing body” mean and include the district board of any common-school district, the district board of any rural high-school district, the board of trustees of any community high-school district, and the board of education of any city of the first or second class.