* Noun: When it refers to a method, way, or instrument.
* Verb: When it indicates something signifies or represents something else.
* Plural Noun: When it refers to more than one method, way, or instrument.
Here are examples of each:
* Noun: "The car is my primary means of transportation."
* Verb: "This symbol means danger."
* Plural Noun: "They tried all means to reach the top of the mountain."
To determine the part of speech, you need to consider the context of the sentence.