Rowan is attested from the 1520s in the sense "fruit of the service tree", adopted via French "sorbe" from Latin "sorbum" "service-berry". "Sorbus domestica" is also known as "whitty pear", the adjective whitty meaning "pinnate". The name "mountain-ash" for "Sorbus domestica" is due to a superficial similarity of the rowan leaves to those of the ash, not to be confused in "Fraxinus ornus", a true ash that is also known as "mountain ash". "Sorbus torminalis" is also known as "chequer tree"; its fruits, formerly used to flavour beer, are called "chequers", perhaps from the spotted pattern of the fruit. The name
Sorbus aucuparia in an alternate leaf pattern on a branch., distinguishing them from those of ash, "Fraxinus excelsior", which are opposite and without stipules. The leaflets are elongated-lanceolate in shape, 2 to 6 cm long, and 1 to 2.5 cm wide with a sharply serrated edge, and have short stems or sit close to the central vein except for the outermost leaflet. Leaflets are covered in gray-silvery hairs after sprouting but become mostly bare after they unfold. Their uppers side is dark green and their underside is a grayish green and felted. Young leaflets smell like marzipan when brayed. The leaflets are