Used to emphasize the finality of one's statement, indicating that one has nothing further to add or elaborate. I'm not going to tell you again. There is no way I am getting on that airplane—period! With our deal, you won't pay $100, only to have hidden fees and charges inflate the bill out of nowhere. If you go with us, you pay $100, period.
exclam. . . . and that’s final! (A way of indicating that there will be no more discussion or negotiation.) My final offer is $30. Period!