1.
year after year; with each passing year
A literary or emphatic expression meaning every single year, emphasizing the repetitive nature of change over time. More formal and literary than 年々.
Year after year the flowers are the same, but people change.
From a famous Chinese poem by Liu Xiyi.
Usage
A literary four-character expression (四字熟語) originating from a Tang Dynasty Chinese poem. More emphatic and literary than the simpler 年々. Often used in reflective or philosophical contexts about the passage of time.
Etymology
From a poem by Liu Xiyi (劉希夷): 「年年歳歳花相似、歳歳年年人不同」— "Year after year the flowers are alike; year after year the people are different."