window, lead enlightenment
牖 centers on an opening that lets in light and understanding: a window in a physical sense, and by extension, the idea of leading someone toward enlightenment or insight.
牖 combines 片 (a split piece of wood, often used for flat objects) with 户 (door) enclosing 甫. The structure suggests a wooden opening in a wall, i.e., a window. The extended meaning of enlightenment likely comes from the idea of letting in light.
Picture a wooden frame (片) around a door-like opening (户) with a grid or lattice (甫) inside. This is a window that lets in light and knowledge.
For ユウ, imagine you (ユウ) opening a window to let in fresh air and enlightenment: you -> ユウ, and the window brightens the room.