the.com/jolly roger

means The traditional black flag bearing a white skull and crossbones (or other death imagery) flown by pirate ships to announce their identity and terrify targets into surrendering without a fight.

from The origin is genuinely murky. 'Jolly Roger' shows up in early 18th-century English for pirate flags, but nobody's certain why. One theory ties it to the French 'joli rouge' ('pretty red'), since early pirate flags were sometimes blood-red rather than black — possibly a nod to 'no quarter given.' Another theory links 'Roger' to an old slang term for a vagabond or even the devil ('Old Roger'), since skull-faced flags were already associated with death and the demonic. Some flags before skull-and-crossbones used hourglasses, skeletons, or bleeding hearts — the skull-and-crossbones version simply became the iconic one. No version of the story is confirmed; take the French theory as the leading guess, not a fact.