There is a question I put and it shows me duplicate, what is that mean the word?
And on hold and protected. What is the meaning of those?
Simply speaking our community tries to avoid some kinds of questions:
Questions that are off-topic for some reasons: Cultural issues, dream interpretation, on politics (in Muslim countries) are some of these, beside any thing which is not related to Islam.
See for example some related meta discussions:
Islam SE: Not a Muslim Peer Support Group
Should we allow questions regarding the Arabic language?
Should dream interpretation questions be on-topic?
Questions that are not well explained or lack necessary information, so that the reader needs to guess what is actually asked.
This is due to the fact that we want focused and answerable questions instead of unclear, unspecific, too personal questions as our answers on the other hand should be well elaborated, focused on answering the actual question and any claim to be supported by evidences.
So if a question is closed or put on hold then due to the fact that it is a question of one of the above kinds... this basically means that users (with enough reputation) of the community have voted to close it for some of the reasons and it passed a review queue.
Once it is put on hold or closed nobody is able to post an answer as long as the question was not edited/re-edited and passed a re-open vote queue. Note that in case of a duplicate, by editing you should also make clear why in your opinion your questions is not answered in the duplicate post!
Now to protecting questions this means a question can be protected from answers from new users -1 -10 rep (?)- (actually it is against spammers who create an account to bump in the site and leave some spam or useless comments), this can AFAIK only be done by user with a high reputation and only after a prior spamming act.
All this can be found in our help center!
When a question is closed, no additional answers may be posted to it, although the question and existing answers can still be edited (by users with edit privileges or by suggested edit) and voted upon, and will continue to count for badges. The asker of a closed question may still accept an answer.
Closed questions can be re-opened by users who have sufficient reputation.
If a question has been closed (except as a duplicate), then for the first 5 days, it is marked as “on hold” rather than “closed”. This is meant to convey that the question requires improvement and may be reopened if improved. During this period, if the question is edited, it will be added to the reopen queue. Other than this, there is no functional difference between “on hold” and “closed”.
Although these questions are not marked "on hold" for 5 days, they are still added to the reopen queue if they are edited within that time. Also, if there are pending votes or flags to close a question as a duplicate, the original poster can approve them and the Community user will instantly close it. Other than that, there are no functional differences between duplicate questions and questions closed for other reasons.
For more information on the duplicate close reason itself, see How should duplicate questions be handled?.
When closing a question, a reason must be provided for the action. Not all close reasons are available on all sites. If none of the reasons for closing the question apply, you should probably not vote to close.
Questions in these categories may be closed:
Off-topic: Questions are expected to be on-topic for the site to which they were posted, within the scope defined by the community.
The “off-topic” option provides further guidance. Closers can either select a predefined message which will show in the close reason box, or type in a custom explanation which will be posted as a comment.
Unclear what you're asking: The way the question is currently written, it's hard to tell exactly what is being asked. The explanations in the question are not clear, or it is not clear what kind of answer is expected, or there is not enough information to solve the problem. The question may be reopened if it is clarified or if the missing information is provided.
Too broad: The question must be edited to limit it to a specific problem with enough detail to identify an adequate answer, and not ask multiple distinct questions at once.
Primarily opinion-based: Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.
Definitely not. Closed questions can and should be edited to improve them and address the reasons why they were closed in the first place. If you edit the question within five days of closure, it will be put into a queue for potential reopening. If you don't get around to editing it within five days, or others don't vote to reopen it in the queue, you should raise a meta question to bring it to everyone's attention so it can get more views that might translate into reopen votes.
It's only when a question can't be salvaged that it should move onto the next state - deletion.
Closed questions become eligible for deletion by the community after 48 hours, but users with 20K reputation or more are not subject to this restriction. See here for the rules governing question deletion. See also Do closed questions ever get deleted?
The Community user automatically deletes closed questions in certain cases.
The moment a question gets closed, only the GUI on the desktop site will prevent answering it. The server does not actually block answers to closed questions until 4 hours after it was closed, to prevent people from losing their work if the question gets closed while they're typing an answer.
The GUI limitation does not kick in on the mobile site or mobile apps if you load the question while it is still open, so it's also possible they posted the answer through those means within four hours of closure.