Questions can have one of the following built-in states:
Open This is the default state for new questions and questions without answers. An unanswered question will appear as open unless it has been manually set as resolved.
Pending A question is marked as pending when a moderator posts an answer.
Resolved A question is automatically set as resolved when an answer is selected. A question can also be manually set as resolved by the owner or a moderator.
State should not be confused with status. The status refers to the publication status (i.e. published, unpublished, trashed, etc) while the state refers to the question workflow (resolved, open, pending).