People who don't surf on TOR (The Onion Router with integrated Firefox) or with Brave (https://brave.com/ome363) are not clear on the difference between Deep Web and Dark Web.
In general, the term Deep Web is used (it also includes the Ｄａｒｋ Ｗｅｂ or also called Darknet).
Let me explain the differences.
CLEAR WEB: This is the Web accessible with any browser (Edge, Chrome, Brave, Opera, etc).
All sites are indexed and easily accessible.
But which sites am I referring to? Google, Youtube, BBC, Gazzetta dello Sport, open forums, blogs, etc.
DEEP WEB: here we find non-indexed or "closed" sites. But what are the non-indexed sites? All those sites excluded from the search engines (many P2P files, racist, violent content, etc.) but also restricted access pages (private profiles of Instagram, Facebook, Twitter but also Paypal, Postepay, banking sites, etc).
To navigate I use a normal browser (Chrome, Opera, Firefox, etc.) but very often I also need a "user" and "password".
DARK WEB: well, things get much more complex here because the sites have different domains and are accessible through modified browsers (TOR, Brave with TOR, Freenet, I2P, Osiris, anoNET, Zeronet, etc.).
For example TOR uses the onion connection, Freenet uses localhost, other networks are based on P2P protocols.
The Dark Web cannot be accessed with Chrome or Edge.
We can say that the Dark Web is a subset of the Deep Web.
These networks are almost anonymous (especially using Whonix, VPN and other precautions) so we can run into black markets (where it is possible to sell drugs, cracked software, weapons, fake documents, etc).
But how do you pay? With virtual coins such as Bitcoin, Monero, Ethereum, Litecoin, etc.
The sites are not indexed, although there are lists of grouped Onion sites or particular search engines such as "Not Evil" (searches are not very precise). On the Dark Web there are sites like Hidden Wiki that group many sites (pity that most of them are scams).