1. Plural of decennary; groups or sets of ten, or periods of ten years.
Usage: Rare or archaic in modern usage; more commonly replaced by 'decades' for time periods.

Examples

• The historian divided the empire's history into decennaries for easier analysis.
• Ancient texts sometimes organized events into decennaries rather than individual years.
• The monastery kept records in decennaries, marking each ten-year period with a summary.