Here are some examples:
Noun:
* The word "love" is powerful.
* She didn't understand the meaning of that word.
Verb:
* He worded his response carefully.
* Can you word it differently?
Adjective:
* This is a word game.
* There is a word limit on your essay.
To determine the part of speech for "word," you need to look at how it functions in the sentence.