- botany the basal part of a grass leaf that encircles the stem
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
Examples from the Web for leaf sheath
The leaf consists of the two parts, the leaf-sheath and the leaf-blade.
The leaf-sheath is smooth, imbricating, 1/2 to 1-1/2 inches long.
The leaf-sheath is glabrous or nearly so, with hairs at the mouth.
The leaf-sheath is smooth, loose, the lower often broad and open.
The leaf-sheath is loose, glabrous, striate, margins not ciliate.