還暦
かんれき kanreki; one's 60th birthday (or 61st in the traditional age reckoning system) when one has lived through a full sexagenary cycle
Why it means this
還 (return) + 暦 (the calendar) — 'the calendar comes back round'; one's 60th birthday, when the 60-year zodiac cycle completes, marked by wearing a red cap and vest.
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.