An egg-shaped ovoid of stone, porcelain, wood, or similar hard material, which is inserted into the toe or heel of a sock to hold it in the proper shape and provide a firm foundation for repairs.

plural of premaxillary

(photography) A system of three (not five) mirrors used as a cheaper substitute to a pentaprism in the viewfinders of some single-lens reflex cameras

(very rare) that is characterized by, or indicative of a regression