having only one costa, rib, or ridge.
Botany. (of a leaf) having only one primary or prominent rib, the midrib.
Origin of unicostate
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
biology having only one rib or riblike partunicostate leaves
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012