Salicylal \Sal"i*cyl`al\, n. [Salicylic + aldehide.] (Chem.)
A thin, fragrant, colorless oil, {HO.C6H4.CHO}, found in the
flowers of meadow sweet ({Spiraea}), and also obtained by
oxidation of salicin, saligenin, etc. It reddens on exposure.
Called also {salicylol}, {salicylic aldehyde}, and formerly
{salicylous acid} or {spiroylous acid}.
[1913 Webster]