Item - a line on an accounting sheet, or a specific thing on a tax form
Class - a category or group of people or other things. See also: "class-action lawsuit"
Experience Level - a quick way of gauging whether or not someone can be trusted to handle some difficult task, such as handling complicated retirement funds. Seriously, I once walked in on two money-manager friends talking about the experience level of one of their coworkers and it sounded like they were talking about a role-playing game.
Simply using these sorts of terms in a role-playing game can strongly influence the types of games and players that will come about. Perhaps the "narrativist" revolution is not so bad after all, because of how it has challenged the existing language and terminology of role-playing games which so many people have become complacent about.