main line
Principal railroad track
The main line is the principal route of a railway, as opposed to branches or sidings.
In drug slang, to mainline is to inject directly into a vein—the most direct route to the bloodstream: He started mainlining heroin at nineteen.
The phrase also describes anything central or primary: the main line of argument. (Capitalized Main Line refers to the Philadelphia suburbs.)
Illegal addictive opiate
- injectionSyringe-delivered dose
- veinVessel toward heart
- needlePointed implement for sewing
- intravenousInto the vein
shooting up · addiction · fix · dose · rush · syringe · arm · hit
Marks showing passage
- locomotiveRailway pulling machine
- freightGoods being transported
- conductorOne who directs musicians
- stationFixed stopping point
platform · depot · junction · caboose · railcar · signal · whistle · tunnel
Cylindrical fluid carriers
- valvesFlow-controlling mechanisms
- shutoffFlow-stopping control
- water pressureForce exerted by liquid
- fittingSuitable or proper
drain · sewer · branch · inlet · outlet · manifold · copper · PVC
Having superior influence
- principalChief school administrator
- centralIn the middle, primary
- majorOf chief importance
- leadingGuiding or pacing type
chief · foremost · predominant · mainstream · core · essential · key
Mutual giving and receiving
- switchboardTelephone routing panel
- operatorOne who works machinery
- connectionA joining or relation
- circuitClosed electrical pathway
long-distance · landline · dial tone · rotary · receiver
heroin
Illegal addictive opiate
intravenous · shooting up · addiction · fix · dose · rush · syringe · arm · hit
tracks
Marks showing passage
- locomotiveRailway pulling machine
- freightGoods being transported
- conductorOne who directs musicians
station · platform · depot · junction · caboose · railcar · signal · whistle · tunnel · bridge
pipes
Cylindrical fluid carriers
- valvesFlow-controlling mechanisms
- shutoffFlow-stopping control
- water pressureForce exerted by liquid
fitting · drain · sewer · branch · inlet · outlet · manifold · copper · PVC · connection
dominant
Having superior influence
leading · chief · foremost · predominant · mainstream · core · essential · key
exchange
Mutual giving and receiving
- switchboardTelephone routing panel
- operatorOne who works machinery
- connectionA joining or relation
circuit · long-distance · landline · dial tone · rotary · receiver
- rail yardsswitchyard, marshalling yards, receiving yard, yard crew, yardmaster
- infrastructurehighways, road construction, railway expansion, power grid, roads
- public transitbus, train, subway, metro, tram
- water systemswater pipes, water pipe, water storage, irrigation ditches, water distribution
- lineageancestry, royal dynasties, bloodline, noble houses, dynasty
- transit routessubway lines, bus route, bus routes, tram route, metro lines
main linebranch line
Secondary railway from trunk
spur · branch · feeder line · short line · local line