1. extremely long periods of time; ages
Usage: plural of eon; informal usage for indefinitely long time
2. the largest divisions of geological time, each containing multiple eras
Usage: geological; scientific

Examples

• It feels like eons since we last spoke.
• I’ve been waiting for eons in this line.
• The Earth’s history spans four major eons.
• Eons passed before life appeared on the planet.
• She hadn’t seen her childhood friend in eons.
• The Phanerozoic eon began about 540 million years ago.
• After eons of erosion, the mountains were worn down.