Definitions for "main line"
Ahe principal route of a transportation system, such as a railroad or bus line.
A railroad's primary track that usually extends great distances. It usually carries both freight and passenger trains.
A railway route interconnecting locations of major importance.
That portion of the piping under constant pressure located between the water source or remote control valves or quick coupler valves.
The pipe in an irrigation system that delivers water from the backflow prevention device to the remote control valves. This is usually the largest pipe on the irrigation system, generally under constant pressure and located upstream from the remote control valves.
The pipe which carries water to the station valves. Back to glossary index.
the principal, most important, or most often played variation of an opening or piece of analysis. For example, 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 8.d5 Ne7 is often referred to as the main line of the King's Indian Defense.
in analysis, particularly of the opening, the principal variation used or analysed. See the Analyis section of the Canon.