1Any of several North American ash trees (genus Fraxinus), especially F. pennsylvanica.
2Any of several Australian trees, especially Alphitonia excelsa (family Rhamnaceae) and Orites excelsa (family Proteaceae).
Late 18th century; earliest use found in William Hanbury (1725–1778), Church of England clergyman and horticulturist. From red + ash.
A variety of coal producing ash of a red colour when burned (more fully "red ash coal"); frequently attributive.
Early 19th century (in an earlier sense). From red + ash.