/peuh ral"deuh huyd'/ , n. Chem., Pharm.
a colorless, liquid, cyclic compound, C 6 H 12 O 3 , having a disagreeable taste but an agreeable odor, produced by the polymerization of acetaldehyde with sulfuric acid: used chiefly in the manufacture of organic chemicals and in medicine as a sedative and hypnotic. Also called paracetaldehyde .
[ 1855-60; PAR- + ALDEHYDE ]