• 歯車はぐるま — gear
• 歯科しか — dentistry
• 虫歯むしば — cavity
• 歯並びはならび — alignment of teeth
• 義歯ぎし — artificial tooth, denture
• 乳歯にゅうし — baby tooth, milk tooth
• 歯石しせき — tartar (on teeth)

The shape of the kanji symbolizes teeth in the mouth. In older forms, it showed a row of teeth. Over time, it also came to represent something biting or grinding, including mechanical uses like "gear."