What is "mesityl"

Mesityl \Mes"i*tyl\, 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.

n. (context organic chemistry especially in combination English) The divalent radical (CH₃)₂=CH-C(CH₃)=