years since the start of an era
Used in historical or chronological contexts to count years from the beginning of a specific era or reign.
この石碑には、建国からの紀年が刻まれている。
This stone monument is inscribed with the years since the founding of the nation.
calendar era; year numbering system
Compound of 紀 (chronicle, era) and 年 (year). The exact historical derivation is uncertain.