# Regression Meaning: Why “It Broke Again” Has a Name

> A bug or error that appears in software after a recent code change, causing previously working features to break or behave incorrectly.

- **Term:** regression
- **Part of speech:** noun
- **Pronunciation:** /rɪˈɡreʃən/
- **English level (CEFR):** B2
- **Register:** Neutral, Both
- **Region:** US and UK
- **Topic:** [Code and Git terms](https://app.speaktechenglish.com/learn/topics/software-development-terms.md)
- **Lesson:** https://app.speaktechenglish.com/learn/regression
- **Last updated:** 2026-10-27

## Meaning

A bug or error that appears in software after a recent code change, causing previously working features to break or behave incorrectly.

In software development, a regression is when a new feature, bug fix, or code update accidentally breaks something that was working before. This is one of the most common problems teams face during development and testing. Regressions happen because changes in one part of the code can have unexpected effects on other parts. Teams run regression tests to check if recent changes broke any existing functionality. Catching regressions early is critical because if they reach production (live users), they damage the product quality and user trust.

## When you hear it

Our latest update caused a regression in the payment system, so we rolled back the changes.

## Examples

- **in a standup:** "I found a regression—the user profile page is now throwing a 500 error after yesterday's changes."
- **in a code review:** "Have you tested this thoroughly? I'm worried it might introduce a regression in the checkout process."
- **in a team meeting:** "We should add regression tests to our CI pipeline to catch these issues automatically."

## What native speakers say

- "We introduced a regression in the login flow"
- "This is a regression from the last release"
- "We need to run regression testing before deployment"

## Common mistakes

- ✗ "We need to regression the code." → ✓ "We need to regression-test the code, or: We need to check for regressions." (Regression is a noun describing the problem, not a verb. You cannot regression something; you test for regressions or fix a regression.)
- ✗ "The regression happened because of a statistical error." → ✓ "The regression happened because our code change broke the API." (In tech context, regression means a bug from code changes, not a statistical calculation issue.)
- ✗ "We will regression this issue." → ✓ "We will investigate this regression, or: We will regression-test this module." (Regression should be used as a noun or in compound nouns like regression test, not as a verb in this context.)

## Be careful

Do not confuse with statistical regression (data analysis). In software, regression always means a bug that appeared after a code change.

## Word forms

| Part of speech | Word | Example |
| --- | --- | --- |
| noun | regression | We discovered a critical regression in the payment module. |
| adjective | regression testing | Regression testing is essential before every release. |
| adjective | regression bugs | The team spent three hours fixing regression bugs. |


## Collocations

- **introduce a regression**: to accidentally create a bug through code changes
- **catch a regression**: to find or detect a regression, usually through testing
- **regression testing**: testing that checks if recent changes broke existing features
- **regression suite**: a collection of automated tests designed to find regressions
- **critical regression**: a serious regression that severely impacts the product

## Synonyms

- **bug**: Bug is more general; regression is specifically a bug caused by recent changes.
- **breakage**: Breakage is more informal and colloquial; regression is more precise.
- **defect**: Defect is formal but does not imply the change caused it, unlike regression.

## Opposites

- improvement
- fix
- enhancement

## Practice

This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/regression

## FAQ

### What does regression mean in software engineering?

A regression is a bug or broken feature that appears after a code change. It means something that was working correctly stopped working because of recent modifications. For example, if you update the login system and suddenly users cannot reset their passwords, that is a regression.

### How do you use regression in a sentence at work?

You might say: We found a regression in the dashboard, or We should regression-test before releasing, or This change introduced a critical regression. You can use it as a noun (the regression) or in compound terms (regression test, regression bug).

### Is regression formal or informal?

Regression is neutral and professional. It is used regularly in both formal meetings and casual team conversations. It is the standard technical term in the industry, so using it makes you sound knowledgeable.

### Can regression be used as a verb?

Not directly. You do not regression something. Instead, you use phrases like regression-test, introduce a regression, or catch a regression. The verb forms are separate: test, break, or fail.

### What is the difference between a regression and a regular bug?

A regression is specifically a bug caused by recent code changes. A regular bug could have existed in the code from the start. Regressions are particularly frustrating because they break things that used to work.


## Related

- [rollback](https://app.speaktechenglish.com/learn/rollback.md)
- [QA](https://app.speaktechenglish.com/learn/qa.md)
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