Translated from English as "explanation of origin.

Stemming (or morphological search) is a process whose meaning is to find a common word for all possible forms of the foundation. This is achieved by discarding parts of the word that appear by its declination and modification - suffixes and endings.

Modern search algorithms using stemming, they can search based on the original forms of the word (i.e., taking into account its morphology). This allows you to form the most relevant requests users search results, which display not only options with direct entry, but also with modified options keywords.

The introduction of stemming by search engines greatly complicated life copywriters and rerayers, because now to increase uniqueness texts are not enough just to slip words defined as content duplication - you need to make significantly more mental effort when processing non-unique data.