- mountain ash - any of various trees of the genus Sorbus
--1 is a kind of angiospermous tree, flowering tree
--1 is a member of Sorbus, genus Sorbus
--1 has particulars:- mountain ash, Eucalyptus regnans - tree having wood similar to the alpine ash; tallest tree in Australia and tallest hardwood in the world
--2 is a kind of eucalyptus, eucalypt, eucalyptus tree
- mountain ash, Fraxinus texensis - low-growing ash of Texas
--3 is a kind of ash, ash tree
- mountain ash, Eucalyptus regnans - tree having wood similar to the alpine ash; tallest tree in Australia and tallest hardwood in the world