Wasei kango (和製漢語), from 坊(ぼう) (bō, “section of a town and its streets”) + 主(ず) (zu, “lord, master”). The kanji 坊 originally referred to, in Sinitic, a division of a town and the lanes surrounding it, and gradually shifted to refer to the workshops and other buildings that might be found in such a section, including temples. Thus, the term literally refers to a "temple master", i.e. a head…