This variable contains the prefix used for naming tables in the database used with WordPress. It is defined in [wp root folder]/wp-config.php and is set to “wp_” by default.
This variable comes into play when there are multiple installations of WordPress. The prefix can then be used to identify tables corresponding to a specific installation.
Plugin developers should use this global variable if they want to create separate tables for their plugin. Instead of using some hardcoded value, they should use this global variable. Here is the codex document related to this.
Back to the full list of global variables.
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