TBSN Share definition Flag TBSN is a short way of saying "The box says no." which is a line from the Futurama episode "The Farnsworth Parabox". Guy I: "Hey, you got any porn?" Guy II: "TBSN." TBSN by LaClown November 3, 2008 0 0 Get merch Get the TBSN mug. Buy Now — $32.95 See more merch
