semidouble

[ sem-ee-duhb-uh l, sem-ahy- ]
/ ˌsɛm iˈdʌb əl, ˌsɛm aɪ- /

adjective Botany.

having more petals than those of a single flower but fewer than those of a double flower.

Origin of semidouble

First recorded in 1970–75; semi- + double