1. Small yellow-marked social wasp commonly nesting in the ground
   "Children ran screaming when they disturbed a yellow jacket nest in the garden";
   - yellow hornet, Vespula maculifrons
    
2. A barbiturate (trade name Nembutal) used as a sedative and hypnotic and antispasmodic
   "The doctor prescribed yellow jacket for the patient's insomnia";
   - pentobarbital sodium, pentobarbital [N. Amer], Nembutal, pentobarbitone [Brit]

Derived forms: yellow jackets

Type of: barbiturate, hornet

Part of: genus Vespula, Vespula

Encyclopedia: Yellow jacket