skull and crossbones

noun

1. a representation of a front view of a human skull above two crossed bones, originally used on pirates' flags and now used as a warning sign, as in designating substances as poisons.

skull and crossbones

noun

1. 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

1. 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.)

Word History and Origins

Origin of skull and crossbones¹

First recorded in 1820–30