# comma

/ˈkɑmə/ (US) · /kˈɒmɐ/ (UK)

Source: https://englishreference.com/word/comma
Updated: 2026-08-27

## Senses

### 1. punctuation mark

noun · CEFR A1

the mark (,) used to separate words in a list or to show a small break in a sentence.

For teachers: a punctuation mark used to indicate a slight separation between grammatical elements or to delimit items in a series.

- Please remember to put a comma between the city and the country.
- The editor insisted that the author use an Oxford comma to ensure the list of ingredients was perfectly clear to the reader.

### 2. musical interval

noun · CEFR C2 · Technical

a very small difference in pitch between two musical notes that seem almost the same.

For teachers: a minute difference in pitch resulting from different ways of calculating nearly identical intervals, such as the Pythagorean comma.

- The musician explained how a comma affects the tuning of the piano.
- In historical temperament studies, the syntonic comma represents the small frequency discrepancy between four perfectly tuned fifths and two octaves plus a major third.

### 3. butterfly

noun · CEFR C2 · Technical

a type of butterfly that has a white mark shaped like a comma on its wings.

For teachers: any of various nymphalid butterflies of the genus Polygonia, characterized by a comma-shaped silver or white mark on the underside of the wings.

- We saw a beautiful comma butterfly resting on a leaf in the garden.
- The Comma butterfly is easily identified by its ragged wing edges and the distinctive white C-shaped mark on its hindwing underside.

### 4. to add punctuation

verb · CEFR C2 · Formal

to put commas into a piece of writing.

For teachers: to insert commas into a text for the purpose of punctuation or delimitation.

- The student had to comma the long paragraph to make it easier to read.
- The manuscript was heavily commaed by the proofreader to conform to the house style guide.

## Examples

- Please put a comma after the word 'yes'.
- When writing a list of groceries like apples, bread, and milk, you should use a comma to separate the items.
- The placement of a single comma can fundamentally alter the meaning of a legal contract, leading to disputes that cost companies millions of dollars in unforeseen liabilities.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.