Semidouble /(?)/

Sem·i·dou·ble

Semidouble

n.
  1. An office or feast celebrated with less solemnity than the double ones. See Double, n., 8. (Eccl.)

Semidouble

a.
  1. Having the outermost stamens converted into petals, while the inner ones remain perfect; -- said of a flower. (Bot.)