mainline

[meyn-lahyn, -lahyn]

verb (used without object)

Slang.

mainlined, mainlining 

1. to inject a narcotic, especially heroin, directly into a vein.

2. to use or enjoy something without restriction.

   to mainline on TV movies.

verb (used with object)

Slang.

mainlined, mainlining 

1. to inject (a narcotic, especially heroin) directly into a vein.

2. to use, enjoy, or imbibe (something) without restriction.

   mainlining coffee all day long.

adjective

1. having a principal, established, or widely accepted position; major; mainstream.

   the membership of mainline churches.

Word History and Origins

Origin of mainline¹

1935–40, v., adj. use of main line

Example Sentences

Alaska faced a similar outage just three months ago when a critical piece of hardware at a data center failed, bringing down its systems and forcing it to cancel about 10% of its mainline schedule.

Read more on The Wall Street Journal

In July, Alaska canceled dozens of flights, or about 10% of its mainline schedule, after a critical piece of hardware at a data center failed, bringing down airline systems.

Read more on The Wall Street Journal

Across the mainline rail network, harassment and common assault made up more than three quarters of the total assaults, and both of these categories saw an increase.

Read more on BBC

We could argue the many, many inhumane points of Trumpist decrees if we were actually interested in discussing policy or, say, the mainline Christianity I once knew as a Presbyterian.

Read more on Salon

With that guidance, officials canceled plans to transfer most of the inmates to mainline prisons.

Read more on The Wall Street Journal

Related Words

• dominant 
• key 
• leading 
• main 
• major 
• outstanding 
• paramount 
• predominant 
• preeminent 
• primary 
• prime 
• prominent