(ˈkrɒsˌbʌk) n1. (Railways) dialect (in the US) a white cross-shaped road sign used at railway crossings2. (Crafts) a strengthening bar attached to the planks of a door
cross•buck
(ˈkrɔsˌbʌk, ˈkrɒs-)
n. an X-shaped warning sign for vehicular traffic at a railroad grade crossing.