We believe you have the right to sell your story for print purposes. You only licensed certain digital rights (the "online medium") and the grant does not include the magic words "print" or "publish." For similar reasons, we believe that eBook rights fall outside the license but that's a more nuanced issue.
The backstory on eBook rights. There's been considerable dispute as to whether older publishing contracts restrict rights for newer formats. In one case, a publishing contract granting rights to "print, publish and sell in book form” was held not to encompass eBook rights. In another case, a contract granted rights in "book format." The agreement also included a clause that the publisher, “shall grant no license without the prior written consent of the Author… including uses in storage and retrieval and information systems, and/or whether through computer, computer-stored, mechanical or other electronic means now known or hereafter invented…” A judge held that this clause prevented the author from separately exercising eBook rights. You can read more about the legalities of interpreting electronic publishing rights, here.
Is an eBook distributed through an online medium? Your contract prohibits you from allowing "any other person or entity to copy, use, display, perform, distribute or modify the Work through or in the online medium." As we noted, the grant does not include the words "print" or "publish," nor does it reference a "book form" such as an anthology. Because the grant lacks the broad language of other publishing agreements ("electronic means now known or hereafter invented") and because it refers to "display", we think it applies only to traditional websites, blogs and other online reproduction. We don't think that the eBook distribution channels as popularized by iBooks and Kindle -- and which did not exist at the time you sold your story -- are included. It really comes down to how broadly a judge interprets the language, "the online medium," something we cannot predict with certainty.