papilionaceous (puh-pil-ee-uh-NAY-shuhs) adjective
1. Of or pertaining to a butterfly.
2. Belonging to the Papilionaceae family whose plants have petals in the form of a butterfly, mostly legumes, such as peas and beans.
[From Latin papilion-, stem of papilio (butterfly).]
When you're sitting in a pavilion, you're under the wings of a butterfly, etymologically speaking. Also, there is a breed of spaniels named papillon having large ears resembling the wings of a butterfly.
Pictures of Papillon and Pea flower.
"`You have an exorbitant auditory impediment,' replied the doctor, ever conscious of the necessity for maintaining a certain iatric mystique, and fully aware that `a pea in the ear' was unlikely to earn him any kudos. `I can remove it with a fishhook and a small hammer...' Dr. Iannis returned at six o'clock and hooked the softened pea successfully without the aid of a hammer, small or otherwise. He worked it out deftly enough, and presented it to the couple for their inspection. Encrusted with thick dark wax, rank and malodourous, it was recognisable to neither of them as anything leguminous. `It's very papilionaceous, is it not?' enquired the doctor."
Louis de Bernières, Corelli's Mandolin, Vintage Books, Sep 1995.