Wiktionary
n. Reasonably pure ethyl alcohol for industrial purposes that has been made unfit for consumption by the addition of a poisonous substance such as acetone or methyl alcohol
WordNet
n. ethyl alcohol that is unfit for drinking but is still useful for other purposes
Wikipedia
Denatured alcohol, also called methylated spirits or denatured rectified spirit, is ethanol that has additives to make it poisonous, somewhat bad tasting, foul smelling or nauseating, to discourage recreational consumption. In some cases it is also dyed.
Denatured alcohol is used as a solvent and as fuel for alcohol burners and camping stoves. Because of the diversity of industrial uses for denatured alcohol, hundreds of additives and denaturing methods have been used. The main additive has traditionally been 10% methanol, giving rise to the term "methylated spirits". Other typical additives include isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and denatonium.
Denaturing alcohol does not chemically alter the ethanol molecule. Rather, the ethanol is mixed with other chemicals to form an undrinkable solution. For many of these solutions, there is no practical way to separate the components.
Usage examples of "denatured alcohol".
She seemed enveloped in aromas of denatured alcohol, tincture of iodine, and the distinctive smell of adhesive tape.
Unless you think it's possible to live in a ninety-six-percent solution of denatured alcohol?
Into the bag went oven cleaner, Raid, Brasso, household ammonia, denatured alcohol, and a box of ant motels.
The only smell that could be defined was that of denatured alcohol.
The odors that arose from the wagon were noxious--the barrels were filled with spoiled linseed oil, denatured alcohol, poisonous lac, bags of salt crystals, and colored powders that she didn't even recognize.