Webster’s Revised Unabridged Dictionary · 1913
Mesityl
Mes′i·tyl (mĕs′ĭ·tĭl), n. (Chem.) A hypothetical radical formerly supposed to exist in mesityl oxide.
Mesityl oxide (Chem.), a volatile liquid having the odor of peppermint, obtained by certain dehydrating agents from acetone; — formerly called also dumasin.