Howdy Valrie,
That’s a unique bit of text you’re trying to modify. All the typical methods for altering it won’t apply, because it’s not part of a language file and thus not translated or filterable. I can totally see why you want to modify it though, this could benefit usability a fair bit.
In your last post I walked you through creating a theme override. That’s going to be necessary here to. You can override public_html/wp-content/plugins/event-tickets/src/admin-views/meta-box.php . Look on line ~80 to see where it outputs those fields.
What you want to modify is the modules array. Specifically alter this key as I show here:
$modules[ 'Tribe__Tickets_Plus__Commerce__WooCommerce__Main' ] = 'Ticket'
And there you are, it should be renamed to ticket.
Does that all make sense? Cheers!
– Brook