What part of speech is humming?

"Humming" can be a few different parts of speech depending on how it's used:

* Verb: When it describes the action of making a low, continuous sound.

* Example: "The bee was humming in the garden."

* Noun: When it refers to the sound itself.

* Example: "The soft humming of the refrigerator was comforting."

* Gerund: When it acts as a noun, but also describes an action.

* Example: "Humming is a great way to relax."

Let me know the specific sentence you're looking at, and I can tell you the part of speech in that context!