As used in this chapter the following terms shall have the meaning herein given them:
"Appointive members" means all members of a commission other than ex officio members;
"Board" means the board of county commissioners;
"City" includes every incorporated city and town;
"Commission" means a city or county planning commission;
"Council" means the chief legislative body of a city;
"Ex officio members" means the members of a commission chosen from among city or county officials;
"Highways" include streets, roads, boulevards, lanes, alleys, viaducts and other traveled ways;
"Mayor" means the chief executive of a city;
"Municipality" includes every county and city.