A gear with a small number of teeth, especially one engaging with a rack or larger gear. The pinion in the clock mechanism needed to be replaced to ensure accurate timekeeping.
The outer part of a bird's wing including the flight feathers. The eagle's pinion was injured, making it difficult for the bird to fly.
A chain, shackle, or other device used to restrain a person's limbs. The captive struggled to break free from the iron pinions that bound his wrists.