1. An academic cap with a flat square with a tassel on top
   "The graduates tossed their mortarboards into the air after the ceremony"
    
2. A square board with a handle underneath; used by masons to hold or carry mortar
   "The bricklayer balanced the mortarboard on one hand while applying mortar with the other";
   - hawk

Derived forms: mortarboards

Type of: board, cap

Part of: academic costume

Encyclopedia: Mortarboard