Definition of "mainline" []

• To inject (a drug, such as heroin) directly into a major vein. (verb-transitive)
• To inject a drug intravenously. (verb-intransitive)
• Being in a principal or well-established position: the mainline churches. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The aim of IRD was then and is now to sow division in mainline churches and church bodies such as the National Council of Churches by defaming church leaders and institutions."
• "Those of us in mainline churches need to be aware that there is a concentrated effort to silence our voice and malign our institutions and leaders so that secular conservative voices in America can push their agenda through without opposition from Christian leaders whom might articulate a different viewpoint – one rooted in the Gospels."
• "Yet he never notices that many of the good things he embraces — for example, equality and opportunity for women — have been championed and better realized in mainline churches and the larger community than in the sciences."