n.
Pronunciation: ˌ pen-t ə - ' bär-b ə - ˌ to ̇ l
Function: noun
Etymology: penta- + -o- + barbital
Date: 1931
: a granular barbiturate C 11 H 18 N 2 O 3 used especially in the form of its sodium or calcium salt as a sedative, hypnotic, and antispasmodic