Stemming is the process of reducing a word to its base or root form, known as a stem. For example, stemming would convert the words “running,” “runs,” and “ran” to their common stem “run.” Stemming helps in reducing the dimensionality of text data and grouping together words that have a similar meaning. Python’s NLTK library provides various stemming algorithms, such as the Porter stemmer, which can be used for stemming tasks.