the.com/main line
the artery everything else hangs off, until it goes down and chaos floods in.
vein slangTo mainline means injecting straight into a vein.
railroadsBranch lines feed traffic onto the busy main line.
philly suburbsThe Main Line is an old-money Pennsylvania region.
plumbingThe main line failing backs up the whole house.
telephonyYour primary phone number is called the main line.