Why does India opal call her dad the preacher?

In the book "India Opal Baloney," India Opal refers to her dad as "the preacher" because he is a preacher and often shares his religious beliefs and values with her. This title reflects both his profession and the moral guidance he provides in her life. Additionally, it signifies their close relationship, as she sees him as a figure of authority and wisdom. The nickname captures the essence of his character and their bond.