Refers to a long period of years, often used in formal or written contexts. Can imply permanence or a very long duration.
He has worked at this company for many years.
My long-held dream finally came true.
long-standing Diet member
Compound of 永 (ei, 'eternal') and 年 (nen, 'year'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning 'many years'.