1. The scientific study of matter in the anus, especially the positions, dimensions, distribution, motion, composition, energy, and evolution of anal bodies and phenomena.
2. Examination of the anus, usealy with a telescope.
After Anal Ella got pounded by a 14 inch cock, she had to go to a special doctor, who was very skilled at the art of asstronomy.
"My uncle Ted knows a lot about asstronomy, I'm sure he could tell you a lot about YOUR ANUS." said Jimmy, who was then promptly beat up.
After Robyn had an asstromomier preform asstronomy on her ass, he found 5 condoms, 3 pounds of seman, 2 pencils, and 1 toy robot.