What are the different acceptance levels in peer review?
In my discipline (CS) in conferences you can find several levels of reviewer recommendations that are different depending on the venue's regulations. You may have:


Strong Accept (+3) 
Accept (+2)
Weak Accept (+1)
Borderline (0)
Weak Reject (-1)
Reject (-2)
Strong Reject (-3)


Not all conference have the same levels. E.g., The Borderline level is not very common (I have only met it in one conference) and Strong Reject or Strong Accept might not be there as well.

Usually, for your paper to be accepted in good conferences, when we are talking about 3 reviewers, you usually need at least 2 weak accepts and 1 accept or something similar. Getting accepted with a weak reject is not very likely, unless the other two reviewers gave an Accept or better, but I do not think this is very common.