mainstay

From Middle English main stai, equivalent to main +‎ stay (“rope”).

• IPA^(key): /ˈmeɪn.steɪ/

mainstay (plural mainstays)

1. A chief support.

   Agriculture is the mainstay of this country’s economy.

   • 2000, Jedrzej George Frynas, Oil in Nigeria, →ISBN:

     Oil is the mainstay of Nigeria's economy.

   • 2014, Marc C. Hochberg, ‎Alan J. Silman, ‎& Josef S. Smolen, Rheumatology, →ISBN, page 307:

     Conventional radiography has a major role in, and remains the mainstay of, initial evaluation and follow-up of rheumatologic disease.

2. Someone or something that can be depended on to make a regular contribution.
   • 2004, Susan McHugh, Dog, →ISBN:

     Like show dogs, dog actors became a mainstay in European and American contexts from the early nineteenth century with the convergence of public sentiment for dogs and popular interest in training them.

   • 2010, Lamar Underwood, 1001 Fishing Tips, →ISBN:

     Crickets are a mainstay of panfishing with live bait—and a mainstay of bait shops—but they come off the hook easily and you'll be plagued by minnows and tiny fish constantly stealing your bait.

   • 2016 May 23, Ignatiy Vishnevetsky, “Apocalypse pits the strengths of the X-Men series against the weaknesses”, in The Onion AV Club‎:

     X-Men: Apocalypse, directed by series mainstay Bryan Singer, gives Magneto, the Holocaust survivor who can control magnetic fields, and Xavier, the paraplegic telepath who tends to come off as really smug, next-to-zero shared screen time.

3. (nautical) A stabilising rope from the top of the mainmast to the bottom of the foremast.

• Mayanist