1. spanning or lasting across multiple millennia; occurring over thousands of years
Usage: formal; often used in academic or scientific contexts

Examples

• The multimillennial history of human civilization reveals patterns of cultural exchange.
• Archaeologists study multimillennial timescales to understand climate change.
• The ancient trade routes had multimillennial significance for connecting distant societies.
• Multimillennial perspectives on language evolution show how dialects diverge over thousands of years.
• The geological record provides multimillennial evidence of Earth's transformations.