That's short for "SQUIRREL" which is what we yell every time we want a reaction out of the dog. Actually, there are a few key words that provide an excited look in her eyes. "RABBIT", "NELSON" and "CHANCY" can all produce a look on her face that we can laugh at, but, "SQUIRREL" tops the list. (And yes, you have to yell with an excitement in your voice, as indicated by all caps)
We saw one run across our path on our afternoon walk and she was heavily fixated on the spot where it disappeared. I'm so going to get in trouble for this, because I am not allowed to let her dig, but I didn't know it was happening until I came upon it. Remember, she's faster than me, especially when fuzzy, furry creatures are involved. Look at that dirt fly!