cm

IPA/sˌiːˈɛm/
IPA/sˌiːˈɛm/

cm — noun

1. a metric unit for measuring short lengths and small distances; one metre split i

1.nounA2
Definition

a metric unit for measuring short lengths and small distances; one metre split into one hundred equal pieces gives one centimetre.

Example

Evelyn measured the table and found it was 120 cm wide.

often used after numbers to describe size

The tiny beetle that Saira found in the garden was only about 2 cm long.

Common collocations
  • cm long
  • cm wide
  • cm thick
  • cm tall
  • per square cm
  • cm in diameter
  • cm of rain
Synonyms
  • centimetre

    the full written form; cm is the standard abbreviation

Grammar Patterns

[number] + cm + [adjective]

Usage Note

This is the standard way to indicate short lengths in Taiwan and most countries. A centimetre is roughly the width of an adult fingernail.

Common Mistakes

The table is 120 cm' (missing an adjective).
The table is 120 cm wide.
cm needs a dimension word like long, wide, or tall after it in a complete sentence.
I need 5 cm of string' (when you mean the string is 5 cm long).
I need a piece of string that is 5 cm long.
cm states a dimension, not an amount.

2. the chemical symbol for curium, a radioactive metallic element produced artifici

2.nounC1
Definition

the chemical symbol for curium, a radioactive metallic element produced artificially in nuclear reactors and used in scientific research; the symbol uses a capital C — written as Cm, not cm.

Example

The periodic table shows Cm for curium, which is element 96.

Cm in the periodic table — capital C

Eleni analysed the sediment sample and found trace amounts of Cm present.

Common collocations
  • Cm isotope
  • Cm-244
  • curium (Cm)
  • Cm nuclear fuel
Synonyms
  • curium

    the full element name; Cm is the symbol used in tables and chemical formulas

Grammar Patterns

Cm + verb (element symbol used as a noun in scientific writing)

Usage Note

Key difference: the length unit is cm (all lowercase), while the element symbol is Cm (capital C, lowercase m). In scientific writing, the full name curium is preferred in the main text; Cm appears in formulas and tables.

Common Mistakes

The sample contained 5 cm of curium.' (lowercase cm suggests centimetres).
The sample contained 5 g of curium (Cm).
use capital C for the element symbol to avoid confusion with the length unit.

cm — abbreviation

Word family

Synonym discussion

Sense: noun/1

Cm is the standard written abbreviation for centimetre, used on labels, in forms, and on maps. The full word 'centimetre' is used in speech and formal writing. 'Millimetre' (mm) is ten times smaller — ideal for precise measurements like paper thickness. 'Metre' (m) is the base unit — one metre is one hundred centimetres — and suits larger lengths like room dimensions. 'Inch' belongs to the imperial system common in the US; one inch equals about 2.54 cm. In everyday Taiwan usage, cm is the natural choice for small-to-medium lengths: 'my phone is 15 cm tall' or 'leave a 3 cm gap.'

cm ↗centimetre ↗millimetre ↗metre ↗inch ↗

Common collocations

Nouns

  • cm of rain
  • cm of snow
  • cm of space
  • cm gap

Phrases

  • cm in length
  • cm in width
  • cm in diameter
  • per square cm

Prepositions

  • in cm
  • per cm
  • to the nearest cm

Etymology

FrenchLatinGreekEnglish

The length-unit abbreviation cm comes from the French 'centimètre', formed from Latin 'centum' (hundred) and Greek 'métron' (measure). The chemical symbol Cm has a different origin — it was taken from the surname of physicist Marie Curie (1867–1934), after whom the element curium is named.