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• main
  main

  adjective

  chief in size, extent, or importance; principal; leading.
• Main
  Main

  noun

  a river in central and W Germany, flowing W from the Bohemian Forest in N Bavaria into the Rhine at Mainz. 305 miles (490 km) long.

main

¹ American  

[mayn] / meɪn /

adjective

1. chief in size, extent, or importance; principal; leading.

   the company's main office;

   the main features of a plan.

   Synonyms:

   capital, primary, paramount, prime, cardinal

   Antonyms:

   least, secondary

2. sheer; utmost, as strength or force.

   to lift a stone by main force.

   Synonyms:

   unqualified, pure

3. of or relating to a broad expanse.

   main sea.

4. Grammar. syntactically independent; capable of use in isolation.

5. Nautical.

   1. of or relating to a mainmast.

   2. noting or pertaining to a sail, yard, boom, etc., or to any rigging belonging to a mainmast.

   3. noting any stay running aft and upward to the head of a mainmast.

      main topmast stay.

6. Obsolete.

   1. having or exerting great strength or force; mighty.

   2. having momentous or important results; significant.

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noun

1. a principal pipe or duct in a system used to distribute water, gas, etc.

   Synonyms:

   conduit

2. physical strength, power, or force.

   to struggle with might and main.

   Synonyms:

   might

   Antonyms:

   weakness

3. the chief or principal part or point.

   The main of their investments was lost during the war.

4. Literary. the open ocean; high sea.

   the bounding main.

5. the mainland.

6. Usually mains a main course in a meal.

   The restaurant offers four mains: one chicken, two beef, and one fish.

adverb

1. South Midland U.S. (chiefly Appalachian). very; exceedingly.

   The dogs treed a main big coon.

verb (used with or without object)

1. Slang. mainline.

idioms

1. in the main, for the most part; chiefly.

   In the main, the novel was dull reading.

main ² American  

[mayn] / meɪn /

noun

1. a cockfighting match.

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Main ³ American  

[mayn, mahyn] / meɪn, maɪn /

noun

1. a river in central and W Germany, flowing W from the Bohemian Forest in N Bavaria into the Rhine at Mainz. 305 miles (490 km) long.

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main ¹ British  

/ meɪn /

adjective

1. chief or principal in rank, importance, size, etc

2. sheer or utmost (esp in the phrase by main force )

3. nautical of, relating to, or denoting any gear, such as a stay or sail, belonging to the mainmast

4. obsolete significant or important

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noun

1. a principal pipe, conduit, duct, or line in a system used to distribute water, electricity, etc

2. (plural)

   1. the main distribution network for water, gas, or electricity

   2. ( as modifier )

      mains voltage

3. the chief or most important part or consideration

4. great strength or force (now chiefly in the phrase ( with ) might and main )

5. literary the open ocean

6. archaic short for Spanish Main

7. archaic short for mainland

8. on the whole; for the most part

main ² British  

/ meɪn /

noun

1. a throw of the dice in dice games

2. a cockfighting contest

3. a match in archery, boxing, etc

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Main ³ British  

/ meɪn, main /

noun

1. a river in central and W Germany, flowing west through Würzburg and Frankfurt to the Rhine. Length: about 515 km (320 miles)

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main More Idioms  

More idioms and phrases containing main

• eye to the main chance
• in the main
• might and main

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Etymology

Origin of main¹

First recorded before 900; Middle English noun main(e), mayn(e) “strength, power,” Old English mægen, megen, cognate with Old Norse magn, megin, megn “strength”; Middle English adjective main(e), partly from Old Norse megin-, megn “strong,” partly from Old English noun mægen used in compounds, as in mægen-weorc “mighty work”

Origin of main²

First recorded in 1560–70; origin uncertain; perhaps special use of main ¹; compare main chance

Explanation

When you describe something as main, you mean it's the most important, well-known, or biggest of its kind. The main branch of the post office in a city is usually the largest and busiest. The main theme of your English paper is your thesis, the basic, fundamental thing you're trying to express in your writing. The main road in town is the most busy and populated — in fact, in many places this road is called "Main Street." This adjective describes things that stand out as the most important or prominent in their category. In the thirteenth century, it meant "large or strong," and came from the Old English mægen, "power, strength, or force."

Example Sentences

See Examples For:

main Main

The main character of Maea’s “Pasado/Futuro” No-Movie, the Being, sprang from the show “L.A. Fonts,” in the artist Alfonso Gonzalez Jr.’s backyard.

From Los Angeles Times ● Oct. 2, 2026

The dollar and Treasury yields are currently the main obstacles to gold returning to its broader bullish path, says Simon-Peter Massabni, head of business development at XS.com.

From The Wall Street Journal ● Oct. 2, 2026

So it was quite something to witness velvet-clad Catalan pipers, sashaying down Barcelona's main boulevards, their medieval tunes intermingling with lilting music that accompanied flocks of brightly dressed Chinese performers.

From BBC ● Oct. 1, 2026

Phiri's lawyer, Powell Nkutabasa, told AFP the main allegations were misuse of office, contravening procurement procedures and dealing in "terrorist" property.

From Barron's ● Oct. 1, 2026

Luckily the Hub, the main building where all the Glitch equipment was housed, wasn’t far, and we were hurling ourselves up its wide stone steps within minutes.

From "Glitch" by Laura Martin

The alarming reptile was “last seen in a tree within a residential neighborhood near Main Street and Edinger Avenue,” according to the department’s warning to the public.

From Los Angeles Times ● Sep. 29, 2026

Instead, they received warnings or notices to correct problems for cases in which they were not penalized, an investigation by Capital & Main has found.

From Los Angeles Times ● Sep. 24, 2026

They would include half hourly services during weekdays on the Chiltern Main Line between London and Birmingham, as well as more weekend services.

From BBC ● Sep. 20, 2026

She moved to Denver in January 1973 at age 27, when her first husband, Carl Main, was transferred there to manage a May-Daniels & Fisher department store.

From The Wall Street Journal ● Sep. 18, 2026

Indeed, the railroad stop was located right across Main Street from the resort.

From "Reaching for the Moon" by Katherine Johnson

Related Words

• central
• essential
• fundamental
• leading
• major
• particular
• preeminent
• primary
• prime
• special
• vital