A backlink is a reference from one website to another, typically made through a hyperlink. Backlinks are a key component of Search Engine Optimization (SEO) as they can be considered as "votes" for a page, increasing its authority and relevance in the eyes of search engines.
Backlinks signal to search engines that a website's content is considered useful and trustworthy. Websites with many high-quality backlinks can be ranked higher in search engine results. However, it's important to emphasize that quality is more important than quantity: a few backlinks from authoritative and relevant websites can be more valuable than many links from less trustworthy sources.