It's not uncommon for a search engine to take a word that is searched for, say "vase" or "obscure", and extrapolate the results to include common versions of the word. So using the earlier examples, you'd include "vases" for results of "vase" and conjugations like "obscures", "obscuring", or "obscured" for results of "obscure".

There's a term for this process, I learned it once and we mention it now-and-then as we talk about our own search system (guess what I'm about to report a bug in! ♪), but I've forgotten the term and cannot find it again. Do you know what the term for this is? Is this in fact a common and accepted term?

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    – fredley
    Commented Mar 1, 2013 at 14:50

1 Answer 1


It is Stemming.

A stemmer for English, for example, should identify the string "cats" (and possibly "catlike", "catty" etc.) as based on the root "cat", and "stemmer", "stemming", "stemmed" as based on "stem". A stemming algorithm reduces the words "fishing", "fished", "fish", and "fisher" to the root word, "fish".

You may find that the variant used in a search engine may be a suffix-stripper, that uses a dictionary with rules to remove suffices from words to get back to the stem.

  • Huh. I guess that kinda makes sense, especially the imagery of "stems" coming from a "root" (and I always did think about roots, so at first I kept thinking "branches", maybe?). A quick search on our chat tells me that this is the term that was tossed around internally. Thank you much!
    – Grace Note
    Commented Jan 9, 2013 at 16:55
  • See also What’s the Difference Between Stemming and Lemmatization? Lemmatization includes stemming as well as more general word matching, including synonyms, abbreviations, and typos. Commented Jan 23, 2015 at 22:28

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