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.