Google Analytics (GA4) dimensions & metrics
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A landing page is the first page someone lands on when they visit your website. For example, let's say someone clicks an ad that goes to a clothing page on your website. In this case, the landing page is the clothing page that the user landed on.
The Landing page dimension shows the page path and query string of the landing page. For example, let's say the URL of a landing page is "www.example.com/home?theme=1." In this case, you will see "/home?theme=1" in the "Landing page" column of the report.
In the example from earlier, Page A, Page B, and Page C are all landing pages. Page B would be the landing page users visit most often.
A key difference between Entrances and Landing page is that Entrances is a metric and Landing page is a dimension. The Entrances metric shows the number of times that the first event in a session occurred on a page or screen. The Landing page dimension shows the specific pages that users landed on.