noun
1. : any of various trees of the genus Sorbus: as
a. : rowan tree 1
b. : american mountain ash
c. : western mountain ash
2. : any of several Australian eucalypts (especially Eucalyptus sieberiana and E. regnans ) with deeply furrowed bark suggesting that of old trees of the genus Fraxinus — see australian oak
3. : a low-growing Texas ash ( Fraxinus texensis ) having leaves with mostly five leaflets