Organic Links have two different definitions, making it a slightly slippery term. On the one hand, an organic link is one that was completely unsolicited as a backlink, but nonetheless links back to a given website. On the other hand, some experts say organic links can include those that were solicited, but they must be natural for both websites and no compensation should have been offered in order to generate the link.
In either case, organic backlinks are considered to be highly valuable and a sign that content created on a given website is regarded as authoritative and relevant to web users on other websites. SEO experts therefore search for ways in which to increase organic backlink generation.