Century Dictionary and Cyclopedia
- unicostate Having but one rib; in botany, noting those leaves which have one large vein running down the center, called the midrib. Those having more than one great division are called multicostate.
- unicostate In zoology, having a single costa, rib, or nervure, as an insect's wing.
Chambers's Twentieth Century Dictionary
- adj Unicostate ū-ni-kos′tāt one-ribbed, having but one principal costa, rib, or nervure.