| 経年 | [けいねん, keinen] (n) passing of years; lapse of time; aging; ageing [Add to Longdo] |
| 経年変化 | [けいねんへんか, keinenhenka] (n, vs) change over the years; aging; ageing; secular change [Add to Longdo] |
| 経年劣化 | [けいねんれっか, keinenrekka] (n, vs) degradation over time; time-related deterioration [Add to Longdo] |