Does the paper that was accepted by the editor and transferred to the reviewers not mean that the paper got the final acceptance? Or can the reviewers still reject the paper?
The decision of accepting or not a submission for publication does belong to the editor, but accepting the submission for evaluation is not the same as accepting it for publication!
I guess that the process might be different for each publisher, or even for each journal, but my experience of the process is as follows:
Upon receiving a submission, the editor
- verifies that its format follows the guidelines of the journal,
- checks that its content is within the scope of the journal,
- set-up a list of potential referees for the submission.
- The submission can be rejected if any of those three criteria is not fulfilled. If all three are fulfilled, the submission is "accepted by the editor", but only in the sense that the evaluation process will be allowed to go on, at the cost of more people's time.
The referees are sent requests to evaluate the submission or to propose alternate reviewers if they are unable to review it. The process can be iterated various times, until a set of willing reviewers is found, or the editor gives up and "rejects" the submission for lack of willing referees.
Once willing referees have been found (ideally, two or three of them) they are sent the submission (ideally, double blind so that to avoid biases), instructions (ideally, an evaluation form) and a deadline to send their evaluation in.
At the deadline, the editor teases the referees who did not send their review (it happens more often than you would think!) until receiving all the reviews, check them for inadequate comments, and forward them to the authors if judged adequate, along with a decision, typically a) refusal, b) conditional acceptance or c) acceptance.
The process can iterate various times with referees asking questions and requesting corrections and the authors answering or complying, until the editor accepts the submission or fails it (most often following the recommendations from the referees, but not always: it is their decision to make!)
I hope it helps! (And anyone willing to correct or extend my description of the process should feel welcome to do so!)