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