- a small close-fitting peakless cap.；a protective helmet, in particular one worn by jockeys or horse riders.
noun: skullcap, plural noun: skullcaps
- 1. a small close-fitting peakless cap.
- ▪ a protective helmet, in particular one worn by jockeys or horse riders.
- 2. the top part of the skull.
- 3. a widely distributed plant of the mint family, whose tubular flowers have a helmet-shaped cup at the base.
- a small close-fitting cap without a brim.
Oxford American Dictionary