As a verb:
* Meaning: To reduce a word to its stem (the base form of a word).
* Example: "Stemming the flow of information is crucial."
As a noun:
* Meaning: The act or process of stemming.
* Example: "The stemming of the river caused flooding."
To determine which part of speech "stemming" is in a sentence, you need to consider the context and the grammatical role it plays.