Plural donut shapes or Cornflake Girl Ms. Amos

noun

1. A large molding of convex profile commonly occurring as the lowest molding in the base of a column
2. The thickening of a membrane closing a wood-cell pit (as of gymnosperm tracheids) having the secondary cell wall arched over the pit cavity
3. A doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle
4. A smooth rounded anatomical protuberance (such as a bony ridge on the skull)