• Ordinal adjectives:
  • Primary "first", first hand.
  • Secondary "second", second hand.
  • Tertiary "third", third hand.
• In organic chemistry:
  • Primary : functional group attatched to carbon atom connected to 1 or no other Carbon atoms
  • Secondary: functional group attatched to carbon atom connected to 2 other Carbon atoms
  • Tertiary: functional group attatched to carbon atom connected to 3 other Carbon atoms
  • Quaternary: functional group (or usually ion) attatched to carbon atom connected to 4 other Carbon atoms
• In physics, the term primary can refer to the most massive component of a gravitationally bound system: see satellite.
• Primary is sometimes short for primary election.
• A movie: Primary (movie)