Blog address (URL)
Similar to WP_SITEURL, WP_HOME overrides the wp_options table value for home but does not change it in the database. home is the address you want people to type in their browser to reach your WordPress blog. It should include the http:// part and should not have a slash “/” at the end. Adding this in can reduce the number of database calls when loading your site.
define( 'WP_HOME', 'http://example.com/wordpress' );
If you are using the technique described in Giving WordPress Its Own Directory then follow the example below. Remember, you will also be placing an index.php in your web-root directory if you use a setting like this.
define( 'WP_HOME', 'http://example.com' );
Dynamically set WP_HOME based on $_SERVER[‘HTTP_HOST’]
define( 'WP_HOME', 'http://' . $_SERVER['HTTP_HOST'] . '/path/to/wordpress' );