100. "COMMISSION" means the Public Service Commission of the State of Mississippi.105. "CUSTOMER" means a person, firm, corporation, association, municipality, the State of Mississippi, the United States, any federal or state department, subdivision or agency, and any institution or establishment whatsoever taking service from a public utility.110. "RESIDENTIAL APARTMENT" means a room or group of rooms used only for living purposes by one family group and which contains the usual or customary kitchen facilities.115. "SEPARATE PREMISES" (See Rule 10.115.)120. "STANDARDS" means those instruments which have been calibrated to give accurate measurement, and are used for comparison with instruments being tested.125. "PUBLIC UTILITY" or "UTILITY" means a public utility as that term is defined in Section 77-3-3, Mississippi Code of 1972, as amended.