1. plural of aeolipile; ancient devices consisting of a hollow sphere or cylinder with bent tubes that spin when steam or hot air is forced through them, often considered an early form of steam engine.
Usage: historical; also spelled aeolipiles; named after Aeolus, the Greek god of wind

Examples

• The ancient Greeks invented eolipiles as curiosities powered by steam.
• Eolipiles demonstrated the principle of jet propulsion centuries before modern rockets.
• Hero of Alexandria described eolipiles in his mathematical treatises.
• These early eolipiles were more toys than practical machines.
• The spinning motion of eolipiles fascinated scholars in antiquity.