mass
mass — verb
1. When people or things mass, they gather in large numbers so that there are many
When people or things mass, they gather in large numbers so that there are many of them in one place, or someone brings them together in this way.
Protesters began to mass outside the city hall just before noon.
intransitive + at/before location
The general massed his troops along the eastern river before the attack.
transitive: mass + troops + location
Dark clouds massed on the horizon as the storm approached.
Reporters massed around the entrance when the celebrity arrived.
The company massed its entire workforce in the main hall for the announcement.
transitive with large group as object
- mass troops
- mass forces
- mass outside
- mass along
- mass around
- mass on the border
- gather
more common and less formal; can describe any size group
- assemble
suggests an organized or purposeful coming together
- congregate
specifically of people, often in a public space
- amass
transitive only; usually means to collect things over time rather than people
Grammar Patterns
mass + adverb/prepositional phrase
mass + object + adverb/prepositional phrase
Usage Note
Subject is usually a plural noun referring to a group (people, troops, vehicles, clouds). The transitive use (mass + object) appears commonly in military and corporate contexts.
Common Mistakes
mass — noun
1. any quantity of material that comes together as a single, formless pile or gathe
any quantity of material that comes together as a single, formless pile or gathering with no fixed outline
A dark mass of clouds gathered above the hills before the storm.
a mass of + noun for a shapeless collection
The volcano sent a hot mass of rock and ash high into the air.
Rachid found a sticky mass of old gum stuck under his wooden desk.
From the airplane, the city looked like a grey mass of buildings and roads.
Indra stirred the flour and water until they formed a sticky mass.
- a mass of clouds
- a mass of dough
- a tangled mass
- a shapeless mass
- a dark mass
Grammar Patterns
a mass of + noun
Usage Note
Often describes natural substances or mixtures whose shape is irregular or changing — clouds, lava, dough, fog.
Common Mistakes
2. an impressively big collection or quantity of people, objects, or material, ofte
an impressively big collection or quantity of people, objects, or material, often seen as overwhelming
The library has a mass of old letters from the nineteenth century.
a mass of + plural noun for a large quantity
Layla received a mass of emails after the company announcement last Monday.
A mass of tourists filled the main square during the summer festival.
There was a mass of information to read before the final exam.
The charity collected a mass of clothes and blankets for local families.
- a mass of people
- a mass of data
- a mass of paperwork
- a mass of complaints
- a mass of detail
Grammar Patterns
a mass of + plural noun or uncountable noun
Usage Note
Used in the fixed phrase 'a mass of' followed by a plural or uncountable noun. Emphasises that the quantity is strikingly large, not just moderately big.
3. most of the members of a group or the largest part of something when it is divid
most of the members of a group or the largest part of something when it is divided up
The mass of students voted to keep the library open until midnight.
the mass of + plural noun = the majority
The mass of the population lives in cities along the coast.
Wei found that the mass of his time went toward research, not teaching.
The mass of the evidence points to one person as the thief.
In a democracy, the mass of voters decides who will lead the country.
- the mass of the population
- the mass of the evidence
- the mass of voters
- the mass of the work
- minority
the smaller part of a group
Grammar Patterns
the mass of + noun
Usage Note
Unlike sense 2 ('a mass of'), this sense always uses the definite article: 'the mass of.' The verb form after it depends on the following noun: singular noun → singular verb, plural noun → plural verb.
Common Mistakes
4. a solid piece of material with an irregular or undefined shape, often formed nat
a solid piece of material with an irregular or undefined shape, often formed naturally or by accident
The doctor found a small mass in Pedro's lung during the X-ray.
a mass in + body part = abnormal growth
A hard mass of clay sat on the potter's wheel, ready to be shaped.
When the metal cooled, it formed a solid dark mass on the factory floor.
The tree had a strange round mass growing low on its thick trunk.
Esteban pulled a sticky mass of melted plastic from the machine.
- a solid mass
- a hard mass
- a sticky mass
- a mass of tissue
- a cancerous mass
Grammar Patterns
a mass of + material noun
a mass in + body part
Usage Note
Common in medical contexts for abnormal growths (tumours, cysts) and in industrial settings for shapeless solid materials left over from a process.
Common Mistakes
5. the broad body of ordinary citizens making up most of a society, seen as separat
the broad body of ordinary citizens making up most of a society, seen as separate from the ruling or wealthy classes
The new tax law was designed to help the masses, not just the wealthy.
the masses = ordinary people as a social group
Television in the 1950s brought entertainment to the masses for the first time.
Cheap smartphones put internet access into the hands of the masses.
The museum opened free evening hours to make art accessible to the masses.
Political leaders often promise big changes, but the masses rarely see real results.
- the masses
- the working masses
- reach the masses
- appeal to the masses
- the voice of the masses
- elite
a small, powerful group at the top of society
Grammar Patterns
the masses
Usage Note
Always plural in this sense — 'the masses.' Often carries political or sociological overtones, contrasting the general public with elite groups (the wealthy, the powerful, the educated).
Common Mistakes
6. a scientific measure of how much matter an object contains, which stays the same
a scientific measure of how much matter an object contains, which stays the same regardless of gravity and gives the object its weight on Earth
The mass of a bowling ball is much greater than the mass of a tennis ball.
mass = scientific measure of the amount of matter
Scientists measure the mass of a planet by studying its gravitational pull.
In physics class, Caio calculated the mass of a small block of iron.
An object's weight can change in space, but its mass stays the same.
The mass of the sample was determined using an electronic balance.
- atomic mass
- body mass
- molecular mass
- calculate the mass
- measure the mass
Grammar Patterns
the mass of + object
Usage Note
In everyday conversation, people often say 'weight' when they mean 'mass,' but the two are scientifically distinct: mass is a fixed property of the object, while weight depends on the pull of gravity.
Common Mistakes
7. the figure you get when you count all the protons and all the neutrons inside a
the figure you get when you count all the protons and all the neutrons inside a single atom's nucleus; this number is what tells one isotope apart from another.
The atomic mass of carbon-12 is 12, with six protons and six neutrons.
mass + of + isotope = total particle count
In chemistry class, Bao calculated the atomic mass of each element on the table.
An atom's mass changes when it gains or loses neutrons.
mass changes with neutron count
To find the mass number, simply add the protons and the neutrons together.
Ravindra explained to the class that uranium-235 has a mass of 235.
mass of [isotope] = [number]
- atomic mass of [element]
- mass number
- mass of [number]
- mass of [isotope]
- mass number
more precise term in physics for the sum of protons and neutrons
- nucleon number
formal synonym used in nuclear physics; less common in general science
Grammar Patterns
mass + of + element
mass + number
Usage Note
Only countable in this sense; often followed by 'of' and the element name or isotope symbol. Commonly used with numbers (e.g., 'mass of 238').
Common Mistakes
8. the small difference between the measured mass of an atomic nucleus and the tota
the small difference between the measured mass of an atomic nucleus and the total mass of the individual protons and neutrons that make it up; this lost mass is released as energy that holds the nucleus together.
The mass defect of a helium nucleus is about 0.7% of the total mass.
mass defect of [nucleus] = percentage of total
Indra learned that the mass defect provides the energy that fuels the sun.
Scientists find the mass defect by subtracting the nucleus mass from the total of its parts.
calculate the mass defect by subtracting...
A larger mass defect means more energy is needed to break the nucleus apart.
larger mass defect = more binding energy
- mass defect of [nucleus]
- calculate the mass defect
- mass defect measurement
- binding energy
the energy equivalent of the mass defect; related but not identical
- mass deficit
alternative term used in some textbooks
Grammar Patterns
mass defect + of + nucleus
the mass defect + verb (is/converts)
Usage Note
Commonly followed by 'of' to specify the nucleus. The concept is central to understanding nuclear binding energy; a larger mass defect corresponds to a more stable nucleus.
Common Mistakes
9. the central religious service in the Catholic Church and some other Christian ch
the central religious service in the Catholic Church and some other Christian churches, where people share bread and wine to remember the supper Jesus Christ shared with his twelve close followers the night before he died; also, a piece of music written to accompany this service.
The Garcia family goes to Mass every Sunday at the church near their home.
go to Mass — fixed phrase for attending
Bach's Mass in B minor is among the most famous works of classical music.
Mass in [key] — musical composition
Father Emre prepared the bread and wine for the Christmas Eve Mass.
A new choir member sang at Mass for the first time last weekend.
at Mass — prepositional phrase for location
The children lit candles during the morning Mass at the old stone church.
- go to Mass
- attend Mass
- Mass in [key]
- morning Mass
- midnight Mass
- say Mass
- celebrate Mass
- Eucharist
formal theological term for the same service; more common in Protestant and academic contexts
- Holy Communion
refers to the part of the service where bread and wine are shared; used in many Christian denominations
- liturgy
the broader set of rituals and prayers, of which the Mass is a specific type
Grammar Patterns
go to Mass
attend Mass
Mass + verb
Mass in [key]
Usage Note
Usually capitalized (Mass) when referring to the religious service. Takes no determiner after 'go to' or 'at' ('go to Mass', not 'go to a Mass'). The uncountable use is common for regular attendance; the countable use ('a Mass', 'three Masses') applies to individual ceremonies.
Common Mistakes
To be completely covered or filled with something.
After the storm, the garden was a mass of broken branches.
His face was a mass of freckles after a week at the beach.
mass — adjective
1. connected with or affecting very many people, or produced in very large amounts.
connected with or affecting very many people, or produced in very large amounts.
Mass unemployment became a serious problem after the factory closed.
collocation: mass unemployment
The government launched a mass vaccination programme across the country.
collocation: mass vaccination / mass programme
Television and social media are the two main forms of mass communication.
collocation: mass communication
The company switched to mass production to lower the cost of each item.
Élise watched a news report about mass protests in the capital city.
collocation: mass protests
- mass production
- mass media
- mass communication
- mass unemployment
- mass vaccination
- mass protest
- mass exodus
- mass starvation
- mass graves
- large-scale
focuses on size/scope of an operation rather than number of people involved
- widespread
emphasises geographic or demographic range rather than production quantity
- extensive
more formal; suggests broad coverage across an area or system
- small-scale
limited in size or number of people involved
- limited
restricted in reach or effect
Grammar Patterns
mass + noun (e.g. mass production, mass media)
Usage Note
Almost always used before a noun (attributive position). Does not follow verbs such as be, seem, or become — you would not say 'the unemployment is mass'.
Common Mistakes
2. considering every member or part of a group as a single unit; viewed or treated
considering every member or part of a group as a single unit; viewed or treated as a whole.
The film had mass appeal and attracted viewers of all ages.
collocation: mass appeal
The mass of data collected by the telescope was too large for one computer.
collocation: mass of data
The festival drew a mass audience from across the island.
collocation: mass audience
A mass meeting of shareholders was held to discuss the merger.
collocation: mass meeting
Ilan studied the mass effect of tourism on the local housing market.
- mass audience
- mass appeal
- mass meeting
- mass of data
- mass effect
- total
more common and less formal; works in many of the same contexts
- aggregate
more formal and technical; common in academic and financial writing
- collective
stresses the group as a whole rather than the sum of separate parts
- individual
focusing on single members rather than the whole group
- partial
covering only a part rather than the entirety
Grammar Patterns
mass + noun (e.g. mass audience, mass of data)
Usage Note
Primarily attributive. Often appears with nouns that refer to groups of people (audience, meeting) or to data sets to indicate a collective view rather than individual details.
Common Mistakes
mass — abbreviation
1. written abbreviation for the US state of Massachusetts, used in postal addresses
written abbreviation for the US state of Massachusetts, used in postal addresses, on official forms, and in news reports to refer to the state.
Darius sent the package to 42 Elm Street, Boston, MA 02109 last Tuesday.
USPS postal abbreviation in full address
Christopher applied to three universities in MA and received offers from two.
state abbreviation in educational context
The Watanabe family settled in a small town in western MA near the river.
Valentina checked the weather forecast for MA before packing her suitcase.
always capitalised, no periods in modern use
The election results in MA were announced late on Tuesday evening.
- Mass.
traditional written abbreviation with a period, used in formal prose rather than postal addresses
Usage Note
Always written in capital letters. The US Postal Service style uses no periods (MA), while the traditional written form 'Mass.' still appears in formal non-address contexts.
Common Mistakes
Word family
- massiveadjectiveB1
- massivelyadverbB2
- massivenessnounC1
Synonym discussion
Sense: noun/1
All four synonyms overlap with 'mass' (noun), but each emphasises a different quality. A 'lump' is a small, compact, often roughly shaped piece — you find a lump in porridge or feel a lump under your skin; 'mass' can describe the same object but focuses on its formlessness rather than its size. 'Bulk' stresses great size or physical weight and often suggests something solid and heavy (the bulk of a ship, the bulk of a man); unlike 'mass,' it rarely applies to soft or fluid substances. 'Volume' is more abstract and neutral — it measures the space something occupies in three dimensions and is the right word in scientific contexts ('the volume of water in the tank'), whereas 'mass' there would mean the amount of matter (science sense 6). 'Majority' refers specifically to the larger number or part of a countable group (the majority of voters) and never to a physical substance; 'mass' in the 'majority' sense (noun/3) uses the definite article ('the mass of'), making it more formal. Example: 'She picked up a lump of clay' (compact, handled) vs. 'She picked up a mass of clay' (shapeless, heavy). 'The bulk of the work is done' (weight/amount) vs. 'The mass of the work is done' (most of it, slightly formal).
Common collocations
Nouns
- mass production
- mass media
- mass transit
- mass communication
- mass market
- mass movement
- mass appeal
- mass unemployment
- mass protest
- mass exodus
- mass graves
- mass hysteria
- mass vaccination
- mass audience
- mass meeting
- critical mass
Adverbs
- mass together
- mass along (the border)
Phrases
- a mass of
- the mass of
- in mass
- the masses
Prepositions
- mass of
- mass in
- mass at
Etymology
The word 'mass' has two separate sources. For the 'lump, quantity, people, physics' meanings: it traces back through Old French 'masse' to Latin 'massa' ('a lump of dough or shapeless material'), borrowed from Ancient Greek 'mâza' (μάζα, 'barley cake, dough'), which comes from 'mássein' (μάσσειν, 'to knead'). Over time the meaning broadened from 'shapeless lump' (14c.) to 'large quantity' (16c.), then to 'the common people' (17c.), and to the scientific sense 'measure of matter' (18c., via Newtonian physics). The adjective use for 'involving many people' emerged in the 19th century with the Industrial Revolution ('mass production', 'mass media'). For the religious sense (Eucharist service), the word comes from a different Latin root: 'missa' ('dismissal'), from 'mittere' ('to send'), referring to the phrase at the end of the service. The spelling convergence of these two distinct words in English is accidental.