# Stemming

Category: [On-Page & Content](https://seo-geo-glossary.com/en/glossary/category/on-page-content/) › [On-page keywords & semantics](https://seo-geo-glossary.com/en/glossary/category/on-page-content/on-page-keywords-semantics/) · Also known as: keyword stemming, word stemming

**Stemming** is a method that reduces inflected or derived words to a common stem, so that "fishing," "fished" and "fisher" are all treated as "fish." Search systems use it to match a query to documents that contain a different form of the same word. In SEO texts the term often appears as "keyword stemming," meaning the use of word variations around a keyword.

## How does stemming work?

Classic stemmers apply rules that strip endings. The stem does not have to be a real word: the Porter-style reduction of "argue," "argued" and "arguing" is "argu" (Wikipedia). According to reports, the first published stemmer came from Julie Beth Lovins in 1968, and Martin Porter's algorithm from 1980 became the standard for English.

Lemmatization is a related method. It looks at the word class and returns the dictionary form, which takes more work but gives real words.

## What does it mean for SEO?

Wikipedia dates Google's adoption of word stemming to 2003. In practice, that means a page does not need to repeat a keyword in every inflected form to be matched with queries that use another form. Writing naturally, with plurals, verb forms and related wording, covers the variations. This reading is an assessment; Google does not publish how its current systems handle word forms.

## Example

A page about "running shoes for beginners" reduces to the stems "run," "shoe" and "beginn." A query for "running shoe beginner" reduces to the same stems, so the page is a match even though the word forms differ.

## Common mistakes

- **Writing a separate page for every word form.** This produces near-identical pages.
- **Forcing variations into the text.** Unnatural repetition of forms reads poorly and does not add information.

## Related terms

- [Semantic search](https://seo-geo-glossary.com/en/glossary/semantic-search/index.md)
- [Keyword research](https://seo-geo-glossary.com/en/glossary/keyword-research/index.md)
- [Keyword stuffing](https://seo-geo-glossary.com/en/glossary/keyword-stuffing/index.md)
- [LSI keywords](https://seo-geo-glossary.com/en/glossary/lsi-keywords/index.md)
- [NLP (natural language processing)](https://seo-geo-glossary.com/en/glossary/nlp/index.md)
- [Lemmatization](https://seo-geo-glossary.com/en/glossary/lemmatization/index.md)

## Sources

- [Stemming – Wikipedia](https://en.wikipedia.org/wiki/Stemming)

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Last updated: October 7, 2026
URL: https://seo-geo-glossary.com/en/glossary/stemming/