# alter

/ˈɔɫtɝ/ (US) · /ˈɒltɐ/ (UK)

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

## Senses

### 1. to change something

verb · CEFR B2 · Academic

to change something slightly, often to make it better or more suitable.

For teachers: to make a structural or formal change to something without replacing it entirely.

- We had to alter our travel plans because the flight was cancelled.
- The researchers were forced to alter their hypothesis after the initial data revealed a significant correlation they had not previously considered.

Usage: Often used with a direct object; can also be used without an object to mean 'to become different'.

### 2. to tailor clothes

verb · CEFR B2

to change a piece of clothing so that it fits you better.

For teachers: to adjust the dimensions of a garment for a better fit.

- The trousers were too long, so I took them to a tailor to have them altered.
- She decided to alter the vintage dress herself, narrowing the waist and shortening the hem to create a more contemporary silhouette.

### 3. to neuter an animal

verb · CEFR C1 · American English

to perform a medical operation on an animal so it cannot have babies.

For teachers: to castrate, neuter, or spay a domestic animal.

- The animal shelter requires all owners to alter their pets before adoption.
- Veterinarians generally recommend that owners alter their dogs at a young age to prevent unwanted litters and certain health complications.

### 4. an alternate personality

noun · CEFR C2 · Technical

one of several different personalities that a person might have in some mental health conditions.

For teachers: a distinct personality state or identity within an individual, typically associated with dissociative identity disorder.

- The patient described how an alter would sometimes take control during stressful moments.
- Clinical observation focused on the transition between the primary identity and a protective alter during the therapeutic session.

Usage: Used as a countable noun in clinical psychology.

## Examples

- I need to alter my plans for the weekend.
- The tailor had to alter the jacket slightly so that it would fit more comfortably around the shoulders.
- Psychologists have found that even minor changes in environment can significantly alter a person's mood and cognitive performance over a long period of time.

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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.