In Google Analytics, a visitor is a unique individual who visits your website. This means that if the same person visits your website multiple times, they will only be counted as a single visitor. On the other hand, a pageview is a record of a single page view. So if a visitor views multiple pages on your website, each of those views will be counted as a separate pageview.
For example, if a single visitor comes to your website and views three different pages, that would be counted as one visitor and three pageviews.
In short, visitors represent the number of unique individuals who visit your website, while pageviews represent the total number of pages viewed on your site. Both metrics are important for understanding how users interact with your website, but they provide different types of information. Visitors give you an idea of how many people are coming to your site, while pageviews help you understand how engaged those users are and which pages are most popular.