* Noun: This is the most common usage. A courier is a person or service that delivers messages, packages, or other items.
* Example: "The courier arrived with the important documents."
* Adjective: This is less common but still valid. It describes something related to couriers or delivery.
* Example: "The company uses a courier service to ship its products."
* Verb: This is the least common usage. It means to deliver something, often using a courier.
* Example: "He couriered the package to her house."
So, the part of speech for "courier" depends on its context in the sentence.