Polyp: A structure consisting of a rounded head attached to a surface by a stalk (also called a pedicle or peduncle). A mushroom growing from the soil is an excellent example of what a polyp looks like. Polyps may be hyperplastic, metaplastic, neoplastic, inflammatory or none of the above. The typical polyps removed from the colon of adults during colonoscopy are benign neoplasms called tubular adenomas or adenomatous polyps. The typical nasal polyps that develop in people with allergies are inflammatory. The common benign polyps removed from the cervix are of uncertain origin.