legion

American  

[lee-juhn] / ˈli dʒən /

noun

1. a division of the Roman army, usually comprising 3000 to 6000 soldiers.

2. a military or semimilitary unit.

3. the Legion.

   1. American Legion.

   2. foreign legion.

4. any large group of armed men.

5. any great number of persons or things; multitude.

   Synonyms:

   sea, host, mass, throng

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adjective

1. very great in number.

   The holy man's faithful followers were legion.

legion British  

/ ˈliːdʒən /

noun

1. a military unit of the ancient Roman army made up of infantry with supporting cavalry, numbering some three to six thousand men

2. any large military force

   the French Foreign Legion

3. (usually capital) an association of ex-servicemen

   the British Legion

4. (often plural) any very large number, esp of people

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adjective

1. (usually postpositive) very large or numerous

Usage

What is a legion? A legion is a large group of people or things, most commonly soldiers, as in World-famous author Stephen King has a legion of fans. Legion can also describe a very large number, as in The number of soccer fans around the world is legion. During the Roman Empire, legion referred to a division of the army that numbered between 3,000 to 6,000 soldiers. As a result, we use legion to refer to a large number of soldiers. However, legion is now used more generally to mean any big group of people or things. Example: The city was filled with legions of fans after the rock star announced they would perform a concert there.

Etymology

Origin of legion

1175–1225; Middle English legi ( o ) un (< Old French ) < Latin legiōn- (stem of legiō ) picked body of soldiers, equivalent to leg ( ere ) to gather, choose, read + -iōn- -ion

Explanation

A legion is a horde or a large number of people or things. It was originally a term for a military unit. In Roman times, a legion was a large unit of men in the army, and the word is still used in many militaries. However, it also means a whole bunch of people doing anything. If someone has many fans, you can say legion of fans or legions of fans, but either way, that's a lot of fans. There are legions of stars in the sky. When you see legion, you can be sure there's an awful lot of something.

Example Sentences

He's one of a legion of often young people seen zipping around some of Britain's cities on bright green hired e-scooters and e-bikes operated by US company Lime.

From BBC • Apr. 3, 2026

Black mascara stained Leerdam’s cheeks as she skated around the arena, saluting the legion of Dutch fans that filled the stands.

From Los Angeles Times • Feb. 9, 2026

Since his arrest, Mangione has attracted a legion of supporters both online and at his court appearances.

From BBC • Jan. 29, 2026

With its trademark improvisational, genre-blending style, the band became known for never performing the same show twice, winning an avid and diverse legion of fans, and selling millions of records.

From Barron's • Jan. 11, 2026

“There will be an investigation. Whoever did this, you cost the legion a good officer. Honorable death is one thing, but this... ”

From "The Son of Neptune" by Rick Riordan

Related Words

• army
• flock
• horde
• multitude
• throng