¹formal

ceremonial, ceremonious, formal, conventional mean marked by attention to or adhering strictly to prescribed forms. ceremonial and ceremonious both imply strict attention to what is prescribed by custom or by ritual, but ceremonial applies to things that are associated with ceremonies <a ceremonial offering>, ceremonious to persons given to ceremony or to acts attended by ceremony <made his ceremonious entrance>. formal applies both to things prescribed by and to persons obedient to custom and may suggest stiff, restrained, or old-fashioned behavior <a formal report> <the headmaster's formal manner>. conventional implies accord with general custom and usage <conventional courtesy> and may suggest a stodgy lack of originality or independence <conventional fiction>.

The Latin word forma, meaning “form” or “shape,” gives us the root form. Words from the Latin forma have something to do with shape. The form of a person or thing is its shape. To conform is to fit in with others in form, shape, or manner. Something formal, such as dinner, follows a specific custom or form. The format of something, such as a book, is its general shape and arrangement.