Noun | 1. | mortarboard - a square board with a handle underneath; used by masons to hold or carry mortar board - a flat piece of material designed for a special purpose; "he nailed boards across the windows" |
2. | mortarboard - an academic cap with a flat square with a tassel on top academic costume - a costume worn on formal occasions by the faculty or students of a university or college cap - a tight-fitting headdress |