mainline
UK: ˈmeɪnlaɪn | US: ˈmeɪnlaɪn
adj. principal or most important (e.g., a mainline railway)
vt. to inject a drug directly into a vein (slang)
n. a major route or pipeline (e.g., a railroad mainline)
The word "mainline" combines "main" (from Old English mægen, meaning "strength" or "primary") and "line" (from Latin linea, meaning "string" or "path"). Originally used for physical routes like railroads, it later expanded metaphorically to describe principal systems (e.g., "mainline churches") and, in 20th-century slang, intravenous drug use—highlighting the directness of the "line" into the bloodstream.
The mainline railway connects all major cities in the country.
Some hospitals still struggle with cases of patients who mainline opioids.
The mainline political parties debated fiercely during the election.
The oil mainline burst, causing an environmental disaster.
Historically, mainline denominations have shaped cultural values in the region.