portland cementport·land cement
a kind of cement that hardens under water, made by burning a mixture of limestone and clay or similar materials
Origin of portland cementfrom resemblance of the concrete made from it to stone quarried on the Isle of Portland, England
or portland cement
A hydraulic cement made by heating a limestone and clay mixture in a kiln and pulverizing the resulting material.
Origin of Portland cementAfter Portland, an urban district of southern England.