°(when referring to a named or numbered decade) Specifically, a period of ten years, beginning on January 1 of a year ending with a zero when written, and ending at midnight on December 31 of the year nine years later.
°(when referring to a named or numbered decade) Specifically, a period of ten years, beginning on January 1 of a year ending with a zero when written, and ending at midnight on December 31 of the year nine years later.