http://schema.org/WebPage supports relatedLink and significantLink which are both of type URL. I don't see, however, the concept of links used anywhere else, and the naming is usually *Url. Moreover, to be more precise semantically shouldn't the relationship be between web pages? Basically a WebPage can be related to other pages or link to other pages, so instead we could have something like
relatedPage and significantSubPage or significantLinkedPage (of type URL or WebPage).
(Practically you could then provide additional information about the linked pages beyond the URL).
http://schema.org/WebPage supports relatedLink and significantLink which are both of type URL. I don't see, however, the concept of links used anywhere else, and the naming is usually *Url. Moreover, to be more precise semantically shouldn't the relationship be between web pages? Basically a WebPage can be related to other pages or link to other pages, so instead we could have something like
relatedPage and significantSubPage or significantLinkedPage (of type URL or WebPage).
(Practically you could then provide additional information about the linked pages beyond the URL).