What does "crossbones" mean?

A representation of two femurs (thighbones) crossed diagonally, chiefly combined with a human skull as a symbol of danger or death.

What is a synonym for "crossbones"?

Common synonyms include: angel of death, ankh, avellan cross, azrael, black death, calvary cross.

Pronounced //ˈkɹɒsbəʊnz//.

/ˈkɹɒsbəʊnz/ noun

noun ·Uncommon ·College level

Noun

1
A representation of two femurs (thighbones) crossed diagonally, chiefly combined with a human skull as a symbol of danger or death. plural, plural-only
2
two crossed bones (or a representation of two crossed bones) used as a symbol danger or death wordnet

"This skull and crossbones was named based on the world-famous Captain Kidd who was active in late 17th century Britain."

From cross + bones.