thujone \thu"jone\ (th[=u]"j[=o]n), n. An oil, {C10H16O}, the chief constituent of cedar leaf oil (thuja oil), which is obtained from the northern white cedar (arbor vitae, {Thuja occidentalis}) or the western Red Cedar ({Thuja plicatis}). It is a stimulant similar to camphor. It is also called {thujol}, {thuyol}, {absinthol}, {thuyone}, {tanacetol}, and {tanacetone}. --Stedman. [PJC]