(ˈ)par+ noun
Etymology: para- (I) + aldehyde
: a colorless liquid of pleasant odor but disagreeable taste that is a cyclic trimer C 6 H 12 O 3 of acetaldehyde formed by adding a drop or two of sulfuric acid to acetaldehyde, that regenerates acetaldehyde on heating with dilute acids, and that is used chiefly as a source of acetaldehyde and as a hypnotic; trimethyl-trioxane — compare metaldehyde