Definition of 十年一昔 (じゅうねんひとむかし)
じゅうねんひとむかし
                        十年一昔
じゅうねんひとむかし
juunenhitomukashi
noun
•
        
the pace of change makes ten years back seem like ancient history(yojijukugo)
Related Kanji
| 十 | ten | 
| 年 | year, counter for years | 
| 一 | one, one radical (no.1) | 
| 昔 | once upon a time, antiquity, old times |