Maomao's name means "Cat Cat" in Chinese. She is depicted as a cat girl when her inner monologue is revealed. It slightly angers her when she is called "Xiaomao", which is not a mere mispronunciation: "xiao" means little or infant, so this name means "Little Cat" or "Kitten".
Adapted from Natsu Hyuuga and Touko Shino's "The Apothecary Diaries" (Kusuriya no Hitorigoto) light novel series.