mainline
Americanverb (used without object)
-
to inject a narcotic, especially heroin, directly into a vein.
-
to use or enjoy something without restriction.
to mainline on TV movies.
verb (used with object)
-
to inject (a narcotic, especially heroin) directly into a vein.
-
to use, enjoy, or imbibe (something) without restriction.
mainlining coffee all day long.
adjective
Other Word Forms
Conjugated Forms
Present
-
has mainlinedperfect 3rd person singular
-
have mainlinedperfect
-
has been mainliningperfect progressive 3rd person singular
-
have been mainliningperfect progressive
-
are mainliningprogressive
-
is mainliningprogressive 3rd person singular
-
mainlinessingular 3rd person
-
am mainliningprogressive 1st person singular
-
mainliningparticiple
Past
-
had mainlinedperfect
-
had been mainliningperfect progressive
-
was mainliningprogressive singular
-
mainlinedsimple
-
mainlinedparticiple
-
were mainliningprogressive plural
Future
Etymology
Origin of mainline
1935–40, v., adj. use of main line
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
“We’ve made it kind of core to who Allegiant is to seek out opportunities that aren’t typically served by mainline carriers,” said Drew Wells, the airline’s chief commercial officer.
From The Wall Street Journal • May 17, 2026
The genius of hit songs, beyond technical artistry—and the vagaries of timing—is the ability to mainline emotion.
From The Wall Street Journal • Mar. 5, 2026
The train operator LNER, which runs the east coast mainline, has extended its advice to passengers not to travel between Edinburgh and Aberdeen as they "cannot guarantee" trains will operate until Friday at the earliest.
From BBC • Jan. 6, 2026
There had been nothing going out on the West Coast mainline and hardly any announcements, she said.
From BBC • Nov. 21, 2025
Like many other evangelicals, some members attend churches that adhere to evangelical doctrine but that remain affiliated with mainline denominations.
From "Class Matters" by The New York Times
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
