What is Hit in Google Analytics?
A user’s interaction on a website that results in data being sent to Analytics.
Hit is the most basic unit in analytics where the data is requested for a small image file.
Each time the tracking code is triggered by a user’s behavior (for example, user loads a page on a website or a screen in a mobile app), Google Analytics saves that activity in the database. Hit types include page tracking hits, event tracking hits, ecommerce tracking hits and social interaction hits.
By default most of the hits are interaction hits, so Google Analytics will use these hits to calculate engagement metrics such as avg. time on page, bounce rate etc.