I know there are several parts of speech:

* Noun
* Verb
* Pronoun
* Adjective
* Adverb
* Preposition
* Conjunction
* Interjection

There might be others as well. Sometimes a word, depending on how it is used, can fulfill more than one of these classes. For example, the word "run" can be a verb:

> 
> I run fast.
> 
> 
> 

or it can be a noun:

> 
> Let's go for a run!
> 
> 
> 

What word, taking into account all its definitions, can fulfill the most word classes?