black flags

from the GNU version of the Collaborative International Dictionary of English.

• An organization composed originally of Chinese rebels that had been driven into Tonkin by the suppression of the Taiping rebellion, but later increased by bands of pirates and adventurers. It took a prominent part in fighting the French during their hostilities with Anam, 1873-85.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Plural form of black flag.