If you don’t know what that means, and would like to know…and if you don’t care, believe me, it’s no great loss, unless you are masochistic enough to want to submit something…it means sending the same query or manuscript two or more places at the same time. Some publications don’t accept simultaneous submissions, like the one (you didn’t really think I was going to tell you which one, did you?) that also informs authors they won’t hear from them for 30-90 days…if at all. My poor little manuscript could die of neglect in 90 days.
BTW I feel so much more professional now that I know the difference between ‘simultaneous’ and ‘multiple.’ At least, I think I do.