# addition

/əˈdɪʃən/ (US) · /ɐdˈɪʃən/ (UK)

Source: https://englishreference.com/word/addition
Updated: 2026-06-19

## Senses

### 1. the act of adding

noun · CEFR B1

the act of putting something extra with something else to make it larger or better.

For teachers: the process of joining or uniting one thing to another to increase the size, number, or importance of the whole.

- The addition of a new park has made the neighbourhood much more popular.
- The addition of fresh herbs at the very end of the cooking process preserves their delicate aroma and brightens the overall flavour profile.

Usage: Often used with the preposition 'of'.

### 2. a new person or thing

noun · CEFR B1

a person or thing that is newly added to a group or place.

For teachers: a person or thing that is added to an existing group, collection, or structure.

- The baby is a wonderful new addition to their family.
- The latest addition to the museum's permanent collection is a rare landscape painting from the seventeenth century.

Usage: Commonly used in the phrase 'addition to'.

### 3. maths operation

noun · CEFR A2

the process of calculating the total of two or more numbers.

For teachers: the arithmetic operation of summing two or more numbers or quantities.

- Children usually learn addition and subtraction before they try multiplication.
- The primary school curriculum focuses on mastering basic addition and subtraction before introducing more complex algebraic concepts.

### 4. chemical reaction

noun · CEFR C1 · Technical

a reaction where two or more molecules combine to form a larger one.

For teachers: an organic reaction in which two or more molecules combine to form a single larger product without the loss of any atoms.

- In this experiment, an addition reaction creates a new compound.
- The hydrogenation of ethene is a classic example of an addition reaction where hydrogen atoms bond to the carbon atoms of the double bond.

### 5. music notation

noun · CEFR C2 · Technical

a small dot next to a musical note that makes it sound longer.

For teachers: a dot placed to the right of a note head to indicate that the duration of the note is to be increased by half.

- The addition of a dot to the half note means it lasts for three beats.
- The composer used rhythmic additions to create a sense of syncopation throughout the second movement of the sonata.

## Examples

- The new baby is a wonderful addition to their family.
- The architect suggested that a glass addition to the back of the house would provide more natural light.
- While the legal team argued that the new clause was a minor addition, the opposing counsel insisted it fundamentally altered the contract's original intent.

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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.