tooth

1. Origins, structure, and basic meaning

• Structure: 歯 has 12 strokes and denotes a tooth or a cog's tooth.
• Basic usage: 歯 is read は, and 歯車 is read はぐるま.

2. Common pitfalls and similar expressions

• Brushing teeth
  • 歯を磨く means to brush one's teeth.
• A mechanical part and an organizational role
  • 時計の小さな歯車 is a small gear in a clock.
  • 組織の歯車として働く figuratively means working as a cog in an organization.
  • として marks the role or capacity in which someone acts.