This is the nickname that Chikagi was called when she was a child. However, perhaps due to going through puberty, she increasingly didn’t like to be called by this name by around the time she entered junior high school, and by the time she entered high school, she had completely forgotten it. Listen to the Drama CD for the rest of the story.

HibiChika Complete Capture Book: Mahou Tsukai no Hako Small Encylopedia