The piping and fittings installed by the serving gas supplier to connect the inlet side of the meter to the gas service and to connect the outlet side of the meter to the customer's house or yard piping
NFPA 54 ANSI Z223.1-2002 National Fuel Gas Code, 2002 ed. https://law.resource.org/pub/us/code/ibr/nfpa.54.2 006.pdf, (Code: Nat Fuel Gas - Amer) {210 NFC}