== As a dab page, a stemmer is... == 

 Stemmer is the title, so all three entries are saying "stemmer". 
 Now if you read the article on Stemming (see above discussions), 
 you will see the word stemmer is a process that includes stemming, 
 but is not limited to it. 
 It may be true that a stemmer and its stemming have opposite directions, 
 (and that the stemming article merged the stemmer article), 
 but this dab page entry is about stemmers, not stemming. —