* Noun: This is the most common use of the word. It refers to the set of fundamental principles or established precedents according to which a state or other organization is governed.
* Example: "The United States Constitution is the supreme law of the land."
* Adjective: This usage describes something as being related to the constitution of a state or organization.
* Example: "The constitutional rights of all citizens must be protected."
* Verb: This use is less common and means to establish or form something, especially a government or body.
* Example: "The delegates met to constitution a new government."
So, without more context, it's impossible to say definitively what part of speech "constitution" is. You need to look at the sentence it's used in to determine its function.