1. relating to or consisting of a period of ten years; occurring every ten years

1. a group or set of ten items or units
Usage: rare; formal
2. a period of ten years
Usage: archaic; formal

Examples

• The decennary celebration marked ten years of the organization's founding.
• A decennary cycle of solar activity influences Earth's climate patterns.
• The museum held a decennary exhibition showcasing a decade of acquisitions.
• In ancient Rome, a decennary was sometimes used to organize military units.
• The decennary review examined progress over the past ten years.