/proh meth"euh zeen', -zin/ , n. Pharm.
a phenothiaxine derivative, C 17 H 20 N 2 S, used for the symptomatic relief of allergies and in the management of motion sickness.
[ 1950-55; PROPYL + ( di ) meth ( ylamine ) + (PHENOTHI)AZINE, components of its chemical name ]