吧哒 (bā dā) is an onomatopoeia that imitates a light, crisp sound — like a quick smack, a tap, or the sound of something small hitting a surface. It is not a common standalone word in everyday speech but appears in descriptive or literary contexts to evoke a short, sharp noise. The character 吧 alone (bā) can also be used for similar sound effects (e.g. a gunshot or a lip smack), but 吧哒 is more specific to a light tap or patting sound.