The chess opening refers to the initial moves of a game. 'Book' openings are well-known sequences that have been extensively studied by professionals and are usually well documented in authoritative references like The Encyclopedia of Chess Openings (ECO).
Where do I find all common openings on Chess.com?
Hover over the 'More' in the left side menu of any Chess.com page
Select 'Openings'
Find an opening that looks interesting to you, and click on it to learn the details.
Once you choose an opening, you'll find detailed information such as its history, pros and cons, and a list of follow-up moves.
You can also explore thousands of games where the opening was played using the 'Explore' section on the right side of the page: