§ 155-a. Definitions. When used in this article: 1. "Districts" shall mean fire districts created pursuant to article eleven of the town law. 2. "Fire companies" shall mean fire companies governed by the not-for-profit corporation law. 3. "Municipal corporations" shall mean a county, city, town and village. 4. "Municipalities" shall mean municipal corporations. 5. "Sprinkler system" shall mean a system of piping and appurtenances designed and installed in accordance with generally accepted standards so that heat from a fire will automatically cause water to be discharged over the fire area to extinguish it or prevent its further spread.