What is the difference between a question and an invitation?

Question

What is the difference between a question and an invitation?

Is there any difference? Do they accomplish different things? Are they structurally different?

Answer 1

I realize that Stephen's answer is pretty thorough, but can't help but think that side-by-side comparison of their definitions may help a bit, so...

Question: Noun: A sentence worded or expressed so as to elicit information.

and

Invitation: A written or verbal request inviting someone to go somewhere or to do something.

So the answer to your question "Do they accomplish different things?" is "Yes". They do. question is for obtaining information, and invitation is more for giving information.

Answer 2

An invitation is a statement or question that says are welcome to a party or an event. A question is something which you want answered.

Example of a question:

Where is your party?

In this example you expect an answer. "The party is at my house."

Examples of an invitation as a statement:

You may come to my party.
You are invited to my party.

Here you just make it clear that the other person may attend.

Example of an invitation as a question:

Will you come to my party?

Both are considered invitations but one expects a response on whether or not you are coming.