1. plural of aeolipile; ancient devices consisting of a hollow sphere or cylinder mounted on an axis, with bent tubes that emit steam to cause rotation, considered an early form of reaction turbine.
Usage: historical; also spelled 'aeolipiles'; named after Aeolus, the Greek god of wind

Examples

• The ancient Greeks built eolopiles as curiosities, not realizing their potential as engines.
• Eolopiles demonstrated the principle of jet propulsion centuries before modern rockets.
• Museums display replicas of eolopiles to show early steam technology.
• The eolopiles invented by Hero of Alexandria were among the first devices to convert heat energy into motion.
• Although eolopiles were ingenious, they remained toys rather than practical machines in the ancient world.