|skull and crossbones|
|a picture of the human skull above two crossed thighbones, formerly on the pirate flag, now used as a warning of danger or death|
skull and crossbones n. pl. skulls and crossbones
A representation of a human skull above two long crossed bones, a symbol of death used as a warning label on poisons.
A picture or outline of a human skull and two crossed arm or leg bones. Pirate ships are supposed to have used the skull and crossbones on their flags. (See also Jolly Roger.)