1. main line - Noun
2. main line - Adjective
the principal route of a transportation system
Source: WordNetEuclid's manner of exposition, progressing relentlessly from the data to the unknown and from the hypothesis to the conclusion, is perfect for checking the argument in detail but far from being perfect for making understandable the main line of the argument. George Pólya
We may summarize the main line of this complexly meandering tale as a list of ironies - invoking the technical definition of irony as a statement where, for humorous or sarcastic effect, the intended meaning of a word becomes directly opposite to the usual sense... Stephen Jay Gould
AMD's main line of business are CPUs and GPUs which primarily go into PCs, servers, and game consoles. Source: Internet
All systems, however, are based on established main line rail systems, and track sharing with inter-city and freight services on parts of the network inhibit higher frequencies on some tracks. Source: Internet
Although these broadcasts contained musical pieces by Schaeffer they cannot be adequately described as part of his main line of musical output. Source: Internet
Construction began in 1870 and the main line opened all the way from the Great Lakes to the Pacific Ocean when former U.S. President Ulysses S. Grant drove its Last Spike in what is now western Montana on September 8, 1883. Source: Internet