Funny thing actually. My friend and I were talking about Harry Potter on Google Chat, and then she said something about how she had read this quote is CoS. Later, my Mom was reading the chat (I don't know why...) and she said "Whats Cos?" (She said it like "Kah" "Oss")
It took her a while to get it.
Now, is it just me, or do those abbreviated names look like Chemistry?