noun
two years before; the year before last
Refers to the year two years prior to the current or reference year. Commonly used in formal or written contexts.
前々年の売上と比較すると、今年は好調だ。
Compared to the sales two years ago, this year is strong.
彼は前々年に大学を卒業した。
He graduated from university the year before last.
前年 means 'the previous year' (one year before), while 前々年 means 'two years before'.
一昨年 is the more common, everyday word for 'the year before last', while 前々年 is more formal and often used in business or written contexts.
Compound of 前 (before) reduplicated with the iteration mark 々, plus 年 (year). The reduplication indicates 'two steps before'.