stemmer

n. person or thing that removes stems

Stemming is the process for reducing inflected (or sometimes derived) words to their stem, base or root form — generally a written word form. The stem need not be identical to the  morphological root of the word; it is usually sufficient that related words map to the same stem, even if this stem is not in itself a valid root. The algorithm has been a long-standing problem in computer science; the first paper on the subject was published in 1968. The process of stemming, often called conflation, is useful in search engines for query expansion or indexing and other natural language processing problems.
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Noun
1. a worker who strips the stems from moistened tobacco leaves and binds the leaves together into books
(synonym) stripper, sprigger
(hypernym) worker
2. a worker who makes or applies stems for artificial flowers
(hypernym) worker
3. an algorithm for removing inflectional and derivational endings in order to reduce word forms to a common stem
(synonym) stemming algorithm
(hypernym) algorithm, algorithmic rule, algorithmic program
(derivation) stem
4. a miner's tamping bar for ramming packing in over a blasting charge
(hypernym) tamp, tamper, tamping bar
5. a device for removing stems from fruit (as from grapes or apples)
(hypernym) device

n. tuner

(n.)
One who, or that which, stems (in any of the senses of the verbs).