Definition of Greek fire in English:

Greek fire

noun

historical
  • [mass noun] A combustible compound emitted by a flame-throwing weapon, used to set light to enemy ships. It was first used by the Greeks besieged in Constantinople (673–8). It ignited on contact with water, and was probably based on naphtha and quicklime.

    • ‘The defenders of the castle were killed off by hunger, plague, or actual weapons such as Greek fire arrows.’
    • ‘It occurred to him that whoever the arsonist was, he must have used Greek fire.’
    • ‘In 1139 the Second Lateran Council decreed that Greek fire and similar burning weapons were ‘too murderous ‘to be used in Europe.’’
    • ‘Their navy first threatened Constantinople in 654, Greek fire being one of the weapons used to defeat this and subsequent armadas.’
    • ‘Cromwell wants Shardlake to pursue two men who claim to have discovered the secret of Greek fire, an ancient weapon of mass destruction, in the hope that it will restore him to the king's favour.’