What does stemming mean?
Stemming most commonly denotes the process of reducing inflected words to a shared base form for tasks such as indexing documents and retrieving search results. For example, a simple stemmer may reduce “connection,” “connected,” and “connecting” to a common form. This helps a search engine retrieve relevant results even when its stored documents and search queries use different grammatical forms. The word can also mean arising or developing from a source, as in “The dispute stems from a misunderstanding.” In botany, the present participle may describe the growth or production of stems. Although stemming is useful in language technology, it is not identical to lemmatization: stemming often removes suffixes mechanically, whereas lemmatization seeks a recognized dictionary form and may account for irregular inflections. The verb sense meaning to stop or prevent something from developing is usually expressed with “stem” or “stem from,” with the latter meaning to originate rather than to halt.
The process of reducing inflected words to a common base form, especially in natural language processing.
"The application applies stemming to both the indexed documents and the user's query."
The term is most common in computational linguistics, search technology, and text analysis. Stemming is generally less linguistically precise than lemmatization.
To arise or develop from a particular source.
"Many of the complaints stem from unclear instructions."
This is normally used in the construction “stem from.” In British English, “stem” may also mean to prevent something from continuing.
To stop, restrain, or prevent something from continuing.
"The committee worked to stem the decline in local industry."
This sense is formal and less common than “stem from.”
To grow or produce a stem, especially in a plant.
"The cutting quickly began stemming in the warm soil."
This botanical sense is uncommon in everyday usage.
As a noun, “stemming” normally names an uncountable process and is used with modifiers such as “word stemming” or “automatic stemming.”
"Automatic stemming improves the consistency of document searches."
Stemming helps search engines find “run,” “runs,” and “running” when a user has typed only one of them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does stemming come from?
The word derives from “stem,” which in Old English referred to a plant's stalk and came to mean a main part, lineage, or the form from which another word is developed. The modern specialized sense associated with language processing developed later through the idea of reducing a word to its basic form. The verb “stem,” meaning to arise from or originate, and the older verb meaning to stop or restrain also contributed to the word's established senses.
Related word forms
How stemming is actually used
In computing and linguistics, stemming usually refers to a relatively mechanical reduction to a base form. It differs from lemmatization, which uses linguistic rules or vocabulary data to produce a dictionary form. In formal prose, “stem from” is common, whereas the plant-growth sense is uncommon and mostly descriptive.