noun
: any of several trees of the family Ulmaceae that prefer or thrive in a moist environment: as
a. : american elm
b. : winged elm
c. : cedar elm
d. : planer tree
e. : a common Eurasian elm ( Ulmus laevis ) that closely resembles American elm
f. : a tall spreading Japanese tree ( Zelkova serrata ) sometimes cultivated as an ornamental