Here are a few examples:
* Noun: "I had a vivid dream last night." (The word "dream" refers to the experience itself.)
* Verb: "I dream of traveling to Europe." (The word "dream" expresses the act of imagining.)
* Adjective: "This is a dream vacation." (The word "dream" modifies the noun "vacation" and describes its quality.)
So, to determine the part of speech of "dream," you need to look at how it is used in the sentence.