kilogram
B1Neutral
Definition
Meaning
A unit of mass in the International System of Units (SI), equal to 1,000 grams.
The primary standard for measuring mass in science, commerce, and daily life; often colloquially used to refer to weight.
Linguistics
Semantic Notes
Strictly a unit of mass, not weight, though in everyday non-scientific contexts, 'kilogram' and 'kilo' are used interchangeably with units of weight (force). The kilogram is defined by the fixed numerical value of the Planck constant.
Dialectal Variation
British vs American Usage
Differences
Spelling is identical. The abbreviation 'kg' is universal. The colloquial clipping 'kilo' is equally common in both.
Connotations
None.
Frequency
Identical high frequency in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
[NUM] kilogram(s) of [NOUN]weigh [NUM] kilogram(s)[NOUN] per kilogramVocabulary
Synonyms
Strong
Neutral
Weak
Phrases
Idioms & Phrases
- “He doesn't have a kilogram of sense.”
Usage
Context Usage
Business
Used in pricing goods sold by weight (e.g., 'Apples are £3 per kilogram').
Academic
The fundamental SI unit of mass, used in all scientific calculations and papers.
Everyday
Used for measuring food, body weight, and parcels (e.g., 'I need a kilogram of flour').
Technical
The unit defined by the International System of Units, with its standard based on fundamental physical constants.
Examples
By Part of Speech
adjective
British English
- A kilogram measurement.
American English
- A kilogram weight.
Examples
By CEFR Level
- The baby weighed three kilograms at birth.
- This bag of rice is one kilogram.
- Could I have half a kilogram of tomatoes, please?
- The recipe requires two kilograms of potatoes.
- Gold is valued at over £50,000 per kilogram.
- The new definition of the kilogram is based on a fundamental constant of nature.
- The spacecraft's thrusters had to compensate for a fuel burn of several kilograms per second.
- Precision scales must be calibrated to the microgram level per kilogram of capacity.
Learning
Memory Aids
Mnemonic
Think 'KILO' (thousand) + 'GRAM'. A thousand grams make one kilogram.
Conceptual Metaphor
WEIGHT IS MASS (in everyday language).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Direct translation is 'килограмм'. No trap, but note Russian speakers might use the plural 'килограммов' where English often uses the singular after a number (e.g., 'five kilogram').
Common Mistakes
- Using plural 'kilograms' after a number when the singular is standard for the unit (e.g., 'He weighs 70 kilogram' is incorrect; correct is '70 kilograms' or '70 kg').
Practice
Quiz
Which is the correct SI unit symbol for kilogram?
FAQ
Frequently Asked Questions
Strictly, it is the SI base unit of mass. In everyday language, it is often used as if it were a unit of weight.
In formal contexts, use 'kilogram' or the symbol 'kg'. In informal speech, 'kilo' is very common.
Use the plural 'kilograms' (or the invariant symbol 'kg') after any number other than one (e.g., 0.5 kilograms, 2 kilograms).
One kilogram is equal to one thousand grams (1 kg = 1000 g).