main

1.adjectiveA2

Definition

the biggest, most powerful, or most significant in a group of similar people or things.

Example

The main road through Kabir's village was closed for a week after the heavy rain.

main road — used for the most important route

Our main reason for moving was that Yasmin found a better job in Taipei.

main reason — used for the biggest factor

Common collocations

main road
main reason
main character
main problem
main difference
main purpose
main entrance
main event
main course
main point

Synonyms

chief
slightly more formal than main; common in job titles (chief executive)
principal
more formal; used in official contexts (principal cause)
primary
focuses on order or priority (primary concern)
key
more informal; emphasises necessity (key factor)

Antonyms

minor
opposite in importance or size
secondary
opposite in order of priority

Grammar Patterns

main + noun

Usage Note

Always placed before the noun it describes. Cannot be used on its own after a linking verb ('the problem is main' ❌ — use 'the main problem is...' ✅).

Common Mistakes

The reason main is the cost.

The main reason is the cost.

main must go before the noun, not after it.

Idioms

with an eye for/on/to the main chance

idiom

Always looking for opportunities to get personal benefit from a situation.

Maya chose her friends with an eye to the main chance.

Brian's decisions are always made with an eye on the main chance.

1.nounB1

Definition

a thick pipe or cable that carries water, gas, or electricity from a central supply network through a neighbourhood so that individual buildings can be connected to it.

Example

A burst water main flooded the street outside Min's apartment building last night.

burst water main — common collocation for a broken supply pipe

The gas main runs beneath the pavement and connects to each house on the block.

gas main — specific type of utility pipe

Common collocations

water main
gas main
burst main
main break
connect to the main
supply main

Synonyms

pipeline
long-distance pipe system; broader than a local main
conduit
technical term for a channel for cables or fluids

Grammar Patterns

the + main

water main

gas main

Usage Note

Often used with a preceding noun that specifies the type: water main, gas main, electricity main. 'The main' alone can refer to any of these when the context is clear.

Common Mistakes

The water main pipe broke.

The water main broke.

main already means the pipe, so adding 'pipe' is redundant.

2.nounB1

Definition

the collection of plumbing and electrical wiring within a property that supplies water and power around the building, or that removes waste water.

Example

Sivan turned off the water at the mains before fixing the leak in the bathroom.

at the mains — fixed phrase for the supply cut-off point

The electrician checked whether the mains could handle the new air conditioner.

the mains — refers to the household electricity supply system

Common collocations

turn off at the mains
mains connection
mains supply
mains water
mains electricity
sewage mains

Synonyms

supply line
American English term for the household connection
service pipe
technical term for the individual building connection

Grammar Patterns

the mains

mains + noun

Usage Note

In British English, 'the mains' (plural) is the standard term for a building's electricity supply. 'Mains-powered' or 'mains-operated' means a device uses the household electricity supply, not a battery. In American English, 'main' (singular) or 'service line' is more common.

3.nounB2

Definition

the specific junction point — usually just inside or outside a building — where an external utility pipe or cable meets the property's internal plumbing, wiring, or drainage system.

Example

The plumber showed Chen where the main was so the new kitchen pipes could join the existing system.

where the main was — locating the junction point between external and internal systems

You need a licensed electrician to connect the solar panels at the main.

at the main — the junction point for connection

Common collocations

at the main
the main connection
connect at the main
turn off at the main

Synonyms

junction
more general term for any joining point
service connection
formal utility company term

Grammar Patterns

the + main

at/from the main

Usage Note

This sense is close to sense 2 but focuses on the physical connection point rather than the network of pipes. 'At the main' is a typical phrase — it means 'at the point where the external supply meets the internal system'.

4.nounA2

Definition

the largest and most filling dish of a meal, usually served after a starter or appetiser and sometimes followed by dessert.

Example

Apinya ordered grilled fish as her main and a small salad to begin with.

as her main — ordering the main course

Jack usually skips a starter and orders only the main when he eats out.

Common collocations

for the main
as a main
main course
main dish
order the main
serve the main

Synonyms

main course
the full form; equally common
entrée
American English term for the main dish; means starter in British English
main dish
less common but still used

Antonyms

starter
the small dish served before the main
dessert
the sweet dish served after the main

Grammar Patterns

the + main

for the main

main course

Usage Note

In restaurant contexts, 'the main' is slightly less formal than 'the main course'. 'Entrée' is used in American English for the main course but in British English 'entrée' means a starter — this can cause confusion for learners.

Common Mistakes

I ordered a main course soup.

I ordered soup as a starter and fish for the main.

soup is normally a starter, not a main course.

5.nounC1

Definition

a fixed phrase used to say that something is true in most ways or with few exceptions — similar to 'generally speaking' or 'for the most part'.

Example

In the main, the students enjoyed the trip to the natural history museum.

In the main, + clause — phrase at the start of a sentence

The food at the conference was, in the main, well prepared and tasty.

was, in the main, — phrase inserted mid-sentence

Synonyms

generally
more common in everyday speech
for the most part
similar formality and meaning
by and large
similar meaning, slightly less formal
mostly
simpler and more conversational

Grammar Patterns

in the main + clause

clause + in the main

Usage Note

This is a fixed adverbial phrase, not a literal use of 'main'. It is common in formal writing and academic texts. In everyday conversation, 'generally' or 'mostly' sounds more natural. The phrase cannot be broken up with possessive adjectives ('in my main' ❌).

Common Mistakes

In the main part, the movie was good.

In the main, the movie was good.

'in the main part' changes the meaning to a literal part-whole reference.

Idioms

Main (river)

idiom

a river in south-central Germany, 325 miles (523 km) long, that rises in northern Bavaria and flows west into the Rhine River near Wiesbaden. It is an important water route for cargo ships and passenger boats.

Sightseeing boats travel daily along the Main river through Frankfurt, passing the historic Römer square and the museums on both banks.

Kabir took a boat trip along the Main from Würzburg to Frankfurt, passing vineyards and medieval castles along the way.

Word family

mainly
adverbB1
mainland
nounB2
mainstream
nounB2
mainstay
nounC1

Synonym discussion

Sense: adjective/1

Main is the most general and common word for saying something is the most important in a group. It fits both concrete things (main road) and abstract ideas (main reason). Chief sounds more formal and is often used for roles or causes (chief executive, chief cause). Principal is also formal and frequent in academic writing (principal objective). Primary emphasises order or priority — the first in sequence or importance (primary school, primary concern). In conversation, main is your safest choice; chief and principal suit formal reports; primary works well for stages or rankings. For example, 'the main issue is funding' sounds natural in any setting, while 'the principal issue is funding' leans formal, and 'the primary issue is funding' suggests it is the first of several issues.

main ↗chief ↗principal ↗primary ↗

Common collocations

Nouns

Adverbs

mainly
principally
primarily

Phrases

in the main

Prepositions

Etymology

Old English (mægen)Middle English (mæin)English

The word main comes from Old English mægen, which meant 'physical strength, power, or force' (still visible in the old phrase 'might and main'). By the 13th century it had shifted to mean 'chief' or 'principal' in importance. The noun senses for utility pipes and wires developed in the 19th century, based on the idea of the 'main pipe' as the primary channel in a drainage or supply system. The river name Main (German: Main) is unrelated — it comes from an ancient Celtic or Germanic river name.

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main

main — adjective

1. the biggest, most powerful, or most significant in a group of similar people or

Grammar Patterns

Usage Note

Common Mistakes

with an eye for/on/to the main chance

main — noun

1. a thick pipe or cable that carries water, gas, or electricity from a central sup

Grammar Patterns

Usage Note

Common Mistakes

2. the collection of plumbing and electrical wiring within a property that supplies

Grammar Patterns

Usage Note

3. the specific junction point — usually just inside or outside a building — where

Grammar Patterns

Usage Note

4. the largest and most filling dish of a meal, usually served after a starter or a

Grammar Patterns

Usage Note

Common Mistakes

5. a fixed phrase used to say that something is true in most ways or with few excep

Grammar Patterns

Usage Note

Common Mistakes

Main (river)

Word family

Synonym discussion

Common collocations

Nouns

Adverbs

Phrases

Prepositions

Etymology

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