I've seen περασμένη and προηγούμενη used somewhat interchangeably and can't figure out the pattern. In particular, I've seen both "περασμένη εβδομάδα" and "προηγούμενη εβδομάδα." Google Translate defines the former as "last" and the latter as "previous," which seem similar to me. My usual dictionary, the ΚΥΠΡΟΣ dictionary at kypros.org (sorry; I can't post links), defines: which again seem similar to me. I also found this post by GreekNative on this forum. The post contains: (emphasis mine) So is there a subtle difference between the two words that I'm missing, or are they really interchangeable?