My sister asked me what this phrase, "sitra achra", means because I used to speak Hebrew, but I'm lost. She thinks it's Hebrew or Yiddish, and if it's Hebrew the closest words I can think of with similar shorashim mean something like a back hiding place... I dunno. So, any ideas? Sorry I can't give it to you in anything but this transliteration... she texted it to me, and if it was written in Hebrew characters before, I think those'd be difficult to text.
Thanks in advance.