Meaning & use
mass
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Meanings
noununcountablephysics
The amount of matter in an object, measured by its resistance to acceleration.
Grammar: Uncountable in physics: measure mass, not a mass; distinguished from weight.
Patterns
- the mass of an object
- have a mass of
- body mass
An object's mass stays the same on the Moon, but its weight changes.
The particle has a mass smaller than an electron.
Doctors use height, mass, and age to assess health.
nouncountable or uncountable
A large amount, number, or collection of something gathered together.
Grammar: Use a mass of for one large group; masses of is informal for very many.
Patterns
- a mass of something
- masses of something
- in the mass
A mass of clouds hid the mountains.
Masses of people waited outside the stadium.
He sorted through a mass of old emails.
proper nounproperreligion
A Christian worship service, especially in the Catholic Church, centered on the Eucharist.
Grammar: Capitalized when naming the service: attend Mass; compare the common noun mass for matter or quantity.
Patterns
- attend Mass
- say Mass
- go to Mass
The family attends Mass on Sunday morning.
The priest celebrated Mass at the cathedral.
Midnight Mass is held on Christmas Eve.
Word forms
| plural | masses |
|---|
Common combinations
- body mass
- Exercise can change body mass over time.
- mass of people
- A mass of people filled the square.
- attend Mass
- Many neighbors attend Mass at the old church.
Synonyms and how they differ
- bulk
- Bulk emphasizes large size or volume; mass is more scientific for matter or more general for quantity.
- pile
- Pile suggests things stacked loosely; a mass can be spread out or compact.
Word family
- massive adjective
- very large, heavy, or serious.
- massively adverb
- to a very large degree.
Commonly confused: mass or weight? mass or mess?
mass vs weight
In everyday speech people mix them, but mass is matter and stays constant, while weight depends on gravity.
mass vs mess
Mass can mean a large amount; mess means disorder or dirt, with a short e sound.
Practice
Which sentence uses the physics sense correctly?
Choose one answer.
Physics mass measures matter and does not change with gravity. The Moon changes weight, not mass; the other options use religious or general-quantity senses.
Make it your own
Write a sentence using “mass”, then check it and compare it with the examples above.