noun, adverb
the week before last
Refers to the week immediately preceding last week. Can be used as a noun or adverbially.
先々週、京都へ旅行に行きました。
I went on a trip to Kyoto the week before last.
その映画は先々週見ました。
I saw that movie the week before last.
Standard kanji spelling using the iteration mark 々.
Alternative spelling without the iteration mark; less common but still used.
Compound of 先 (previous) reduplicated with the iteration mark 々, plus 週 (week). The reduplication shifts the time reference one step further back.