URL parsing – what is it?

Parsing means to analyze (a string or text) into logical syntactic components.

Taking WordPress URLs into the question is something like this:

// Get array of URL 'scheme', 'host', and 'path'.
$url_parse = wp_parse_url( 'https://developer.wordpress.org/reference/functions/wp_parse_url/' );

// Output URL's path.
echo $url_parse['path'];

/*
Array
(
    [scheme] => https
    [host] => developer.wordpress.org
    [path] => /reference/functions/wp_parse_url/
)
*/

Another way to consider is in your WP settings. It breaks it down too:

https://www.example.coom/2019/09/12/sample-post/ is the same as

%scheme%//:%host%/%year%/%monthnum%/%day%/%postname%/

There are other uses for this too. In using the WordPress API you’ll need to know parts of the url (endpoint, version, etc).

Parsing is breaking the url down so you know what the parts are when you’re working with it.