Definition of allonal in English:

allonal

noun

Pharmacology
rare, historical
  • A sedative and hypnotic drug of the barbiturate class. [Chemical name: 5-allyl-5-isopropylbarbituric acid; C10H14N2O3. Originally a trademark in the United States and United Kingdom for a drug that also contained pyramidon.]

Origin

1920s; earliest use found in Spatula. From all- + -onal.

Pronunciation

allonal

/ˈalənl/