What part of speech is one?

"One" can be several parts of speech, depending on its function in a sentence:

* Numeral: When it refers to a single quantity, like "There is one apple on the table."

* Pronoun: When it replaces a noun, like "One should always be respectful."

* Adjective: When it modifies a noun, like "One day, I will travel to Europe."

* Indefinite pronoun: When it refers to an unspecified person or thing, like "One never knows what the future holds."

Let me know if you'd like me to explain any of these with examples!