A high-quality backlink is a link that is obtained from a reputable and authoritative website. This type of backlink can help improve the search engine rankings of the website it is linking to, and it can also drive relevant and targeted traffic to that website. Some factors that can contribute to the quality of a backlink include the relevance of the linking website to the website being linked to, the authority and trustworthiness of the linking website, and the quality of the content on the linking website. Additionally, a backlink is more valuable if it is a "dofollow" link, which is a link that passes along link equity, rather than a "nofollow" link, which does not pass along any link equity.