As used in this article:
(1) The word "municipality" shall mean an incorporated city or town, irrespective of its population;
(2) The term "municipal council" shall mean the governing body of any incorporated city or town;
(3) The term "corporate purpose" shall denote any public purpose, necessary or convenient to the welfare of the municipality and shall include the funding of existing indebtedness, evidenced otherwise than by bonds of the municipality; and
(4) The word "commissioners" shall mean the commissioners of public works or the board of public works or other body established by law and given the power of operating any waterworks system, electric light system, sewage system or other municipal utility.