What is "semidouble"

Semidouble \Sem"i*dou`ble\, n. (Eccl.) An office or feast celebrated with less solemnity than the double ones. See Double, n., 8.

Semidouble \Sem`i*dou"ble\, a. (Bot.) Having the outermost stamens converted into petals, while the inner ones remain perfect; -- said of a flower.

a. (context botany of a flower English) Having the outermost stamens converted into petals, while the inner ones remain perfect. n. An ecclesiastical office or feast celebrated with less solemnity than the double ones.