More “Stupid” Questions

This is a thread where peo­ple can ask ques­tions that they would or­di­nar­ily feel em­bar­rassed for not know­ing the an­swer to. The pre­vi­ous “stupid” ques­tions thread went to over 800 com­ments in two and a half weeks, so I think it’s time for a new one.