yellow jacket

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of several small wasps of the family Vespidae that have yellow and black markings and usually nest in the ground.

Century Dictionary and Cyclopedia

1. n. In Australia, any one of several species of trees having a smooth, yellow bark, especially the yellow box, Eucalyptus melliodora, and the river gum, Eucalyptus rostrata.
2. n. Any one of several species of true social wasps or hornets of the genus Vespa, which have the body more or less marked with yellow; any hornet, as V. crabro. See cut under hornet. Vespa vulgaris, an importation from Europe, is the common yellow-jacket of the United States.

GNU Webster's 1913

1. adj. (Zoöl.) any one of several species of American social wasps of the genus Vespa, in which the color of the body is partly bright yellow. These wasps are noted for their irritability, and for their painful stings.

WordNet 3.0

1. n. small yellow-marked social wasp commonly nesting in the ground
2. n. a barbiturate (trade name Nembutal) used as a sedative and hypnotic and antispasmodic